Where to even start ... oh well I'll start here:
What I hate most about Inquisition is this: all the unearned praise and all the blind idiots who called this unfinished trash GOTY when it only came out at the last possible moment and was so filled with bugs and broken bits to rival a Bethesda release. This game has been my culling. As in I culled my list of reviewers and sites I follow bassed on how many of these imbecils called DA:I "teh best game" because these people clearly do not have any sort of ability to even atempt objective criticism.
Glad I got that out of my system, now time to say my piece:
1) The game is unfished
I mean that. This game should not have seen the light of day. There has been not a single moment while palying it that I felt "Ok, this was well done, this was where the effort went" appart maybe for the post ending cutscene, which only served to make me even angrier at the game. The amount of bugs I've encountered in this game gives launch skyrim a run for it's money, but where skyrim was fixed quickly by mods, DA:I to this day has done almost nothing to adress complaints and reports. 3 patches in and the most significant bug they fixed was removing the glowing hair textures and fixing the scars, both errors that were introduced IN ONE OF THEIR PATCHES. But oh, look at all those lovely multi-player events we are doing! ... not a single fan of the series gives a solitary fuck about the multi-player. And beyond that, as long as your game is broken and filled with bugs, what makes you think I will try your shit multi-player?
But even beyond bugs so many parts of this game feel ... rushed. The Skyhold gave me some meagre hope when I got it, but then I dreaded it for how much tedium it added to the war table crap and companion chat (though that last one vanished when I realized how shallow and uninteresting the companions are). But with only one upgrade that actually means something (the other 2 are cosmetic) and with how even after finding resources to build an entire fucking city I still have holes on the walls ... yeah, I'll skip. And this feeling kept following me through-out the game. Hissing wastes, Emprise du lion ... The hinterlands ... everything felt rushed, boring and cobbled toghether, with no real substance behind. Sometimes there might be glimpses of something interesting (like the surface thaig), but they vanished as soon as they were spotted
2)The story
Oh dear lord ... the story. You know what bioware? I'd rather go back and play Mass Effect 3!!! At least there I can enjoy a somewhat competent story and shut off the game after the suicidal beacon charge and take a bunch of pills to forget about the whole start-child thing. With this crap I have to put in god knows how many hours in a shit, uninteresting, uneventfull story where the main bad-guy is just a manipulated goon of no relevance to the grand scheme that provokes copious amounts of laughter with his retarded look, just so I can get the one part that actually reminds me of the good old DA:O story and makes me want more! And that part is just a pathetic cutscene at the end where my characte had no impact! Fuck this shit. Everything that happens in inquisition, the mage-templar war that seemed like the next big thing of the DA world and the chance to start a new era is rendered completly pointless, and our inquisitor and his mery band as nothing more than glorified pest control to make way for the real plot. Pest control for a guy THAT WAS ALLREADY KILLED AND BURRIED IN DA2: LEGACY! That final scene in inquisition does 2 things: It is the only part of actual fucking interesting lore in the game that forwards the grand conflict of this world; It is also the scene that renders the game pointless in the grand narative. And the rest of the so called plot? Distractions and time-sinks until Morrigan and Flemeth show up to point at the real problem and actually start the plot, that ends 2 hours latter, after 60-80 hours of faffing about. It's fucking Assassin's Creed's storytelling in the Dragon Age universe.
3)The gameplay
There once was a game called Origins. It had an awesome but somewhat clunky tactical interface and some smart strategic combat. The animations were shit, the mages were OP, but it was a good system, it did it's job admirably and it provided and unique aproach to combat.
Then came it's sequel. It strived to improve, and it did in some regards. Warriors became more usefull, mages were tonned down a bit, but it also leaned much more to an action crowd. Still, it did ok.
BEHOLD THE FUTURE: look at our awesome animations! Watch all the blingy lights flying around, whatch as this guy clams an axe in the dirt and cause rock spikes to burst from a sandy beach! Watch as your tactical menu is absent. Behold how you can no longer program actions for your characters and set up combos for them to pull off. Enjoy as they can no longer be told to smartly dodge AOE attacks, or to avoid friendly fire. Behold the tactical camera that is slow, imposible to control and doesn't even allow action queing, on top of beeing obstructed by terain (seriously, a barrel on the ground can stop the camera from moving to target behind the barrel ...). Enjoy how a once tactical game has been reduced to "control most op character->rush into combatp->revive and heal after eveyrthing dies->reload if dead". But damn do does effects look fine, and that makes up for everything, am I right?
No, you are not bioware. Now take this piece of trash and shove it up your ass along with your idiotic and broken knight enchanter.
4)The item system.
So ... we have a diablo style loot system. Ok. We have a crating system that makes the previous system superflous. Umm ... why? Oh relax, we also made sure there are only 3 armors per clas that you can wear and they only differ via some vague details that no one will notice. Oh and they all look like shit. Wha?! What the hell? Oh but there are some unique racial armors and this noice pice of DLC gear that look great! Um ... ok, somewhat bet- Yeah they are all inferior to the shit loking armor and the humans get most of them, elfs get 2 (one mage and 1 rogue) and the dwarfs get 1 for warriors. Um ... bioware this sounds like shit to me so far. Also I want to play a qunari. Well the qunari have no special armor, but they do have this absolutly retarded clown make-up! Enjoy beeing a big ox-man clown dressed in rags!
I hope you enjoyed my little schizo moment there, but on a more serious note: Inquisition has the ugliest designs for armor and weapons I've seen in a while, coupled with a looting system that only gives useless trash and a crafting system that is a pain to use, on top of not providing any sort of amazing looking armor like skyrim had dragon bone and daedric. Also: when you call something a legendary weapon, it would help if it wasn't a toothpick worthy of ants compared to the boring sword I had my blacksmith shit out a few hours ago for a peny and a bunch of comonly available surface ores.
5)The characters (more specifically the companions) & romance.
This game has a special place in my heart. It is the first bioware game where I did not like a single one of the companions you are given. With a caveat: Varric doesn't count. He comes from DA 2 and his appeal was born in that game. In this one his interactions are wasted. They are all such stereotypes and all the words they say can be so easily predicted that they just feel like automatons. The voices feel off too, like the actors are not giving a shit about the role. And with how rushed and unfinished everything is their stories feel unfinished and the relationship between them and the quis feel fake. Like someone before me said "Dude I only shared like 20 words with you since we met, and now I'm your BFF?". And the romance ... oh god the romance. Bioware please stop writting romance in your games. Please. It was an admirable attempt, but now you went and jumped the rails. This is not how romance between 2 human beeings works. Stop it.
6)The world
Which feels empty and padded. Look at how big our virtual dick is, look at how many sqare miles of empty land we added in this game! We are the best!
No bioware, you are not. This game is the MAKO exploration of the first mass effect game.
7)The Inquisition itself.
Yes, this mighty organization that shapes the history of the world, and YOU are the man in charge, deciding when and how to use your forces! How do they convey this? Through a boring impersonal menu system that has no actual impact on the story or characters and no consequances for your decisions (visible consequences, not a pathetic 2 or 3 lines of text that are forgoten the moment you close the window) and just serves to take away even more time as you wait for days (or edit your system clock on the pc) for the mission to end. What a load.
Now I know the question was how to improve inquisition and I realize I focused on all the flaws, but they are all such evident and easily correctible flaws I felt I didn't need to say how they could be fixed. The answer is preety simple anyway: Put some god damned effort next time, don't just phone in this half written half finished garbage.