I'm going to have to highly disagree with this "review", yes, I'm one of the people who think the current edition is worse than the previous one, but hear me out:
1) Assaulting in general.
This was a major problem with 6th edition, assaulting armies were penalized way too harshly (look up virtually any tyranid vs tau friendly game), and this edition has not changed that, in fact, it's done the opposite since now Psykers can throw out a lot more firepower in their new phase, as well as shoot after doing so.
I want to see how any daemon army can lose if they go a greater Lord of Change with four heralds of change, get the grimoire of true names and you can make your screamerstar back up with 4 units that don't even need to specialize in divination, and these four can summon more units, including more Heralds of Change, or allowing themselves to get possessed to summon another Lord of change (who can then summon Heralds), not to mention the fact of demons getting possessed to summon daemons doesn't make any sense. This army expansion means you can effectively double the points worth your army is, keep summoning and you'll easily end with more points than you've started with. Even regular armies can get the ONE warp charge cost needed to summon a herald, who can then start summoning more heralds.
Perhaps the most ridiculous thing is when summoned Lords of change get down to one wound, they can get possessed, to summon a Lord of Change! On the same spot, with an identical profile, all wounds restored.
3) Deny the Witch
So this got a lot harder, because you have to cancel as many successful warp charges as they've used, the odds of rolling all of the 6's you need are incredibly slim because you need to say how much you're going to put towards it before rolling, if you're a 6 short, too bad, you wasted most of your warp charges.
I don't have a problem when Fantasy does this, because in Fantasy your odds are equal, if you have six dice, and they use six dice, and you both have a level 4 wizard, you've got an equal chance of nullifying the spell as they do of casting it.
Here though, they need 4+ to use the power, you need 6+ (as many as they roll 4+) to deny it.
4) Unbound Armies.
A while ago GW came out and publicly said they don't care about game balance: http://natfka.blogspot.co.uk/2014/01/an-interesting-conversation-with-gw-rep.html
This pretty much proves it. It's now possible to make whatever army you want, against whoever you want, and if they don't like it, then too bad, the rules said they could do it. The reason some armies worked well was because you blanced out some units by making sure the players could not take so many, with this in there what reason is there to not spam all of your best troops for no reason, like making an entire army out of Heralds/Lords of Change (besides it being a really assholish thing to do)?
All hail the all flyer list when fighting against Orks/Space wolves, all hail the almost all Heldrake list, all hail Riptide spam, all hail the Flyrant swarm. Come to think of it, Flyers are still broken as hell (since their rules didn't change) but now even more so because you aren't constrained to the usual 3 (plus transports) you'd normally have, now you can have as many as you want and just overwhelm their AA defence while staying virtually untouchable.
Anyway, that's why I don't like this edition, for the positives I think summoning demons is pretty neat, but far too easily abusable, I think the new Psychic Phase is neat, but that's it's far too hard (and statistically impossible) to counter, and those were really the only two things that changed in this edition, it didn't fix any of the problems of the previous one, and introduced several new problems when it arrived.
One more thing about this review, I'm not sure it can be called a review, almost all of it is spent explaining what's in the books, instead of going over the positives and negatives of the new edition, it's like watching a game review where the reviewer explains how to play the game for the first 4 minutes 30 seconds of the 5 minute review, then just drops a blurb about how the game is good.