Fallout 4, it's a great example of how to do an open world correctly where every location is unique
Sorry but no, this is a lie. Every location is basically the same and none of them are interesting. You will only find raiders or feral ghouls. Occasionally things might get exciting and you find some raiders fighting feral ghouls.
MGSV's world, while barren, between the checkpoints and camps, at least went to the effort of making them different, and makes any approach viable. It's the whole quality over quantity thing.
You have a REASON to explore the bigger camps in MGSV. Blueprints, soldiers to kidnap, resources are all thing you actually need. You need them to get better equipment and base security for FOBs etc.
Fallout 4's only reason to explore Abandoned House #393 is for materials for the base building aspect, which is fun for about 10 minutes until you realise there's no reason at all to do it. Fallout 4 actually punishes you for exploring most of the time, which is amazing but true. After fighting your way through a maze of raiders and spending all your ammo (because the game subscribes to a "give enemies more health = higher difficulty" method) you're rewarded with ANOTHER modded pipe weapon which will almost certainly be inferior to your current weapon. So now you have less ammo and only a useless weapon and a bit of XP to show for it. Arguably, you have less stimpacks, but after 10 hours I had 70+ of them.
Oh, and lets not forget that the crafting is locked behind about 4 different perks, and often, multiple upgrades of perks. I spent levels 18-26 (ish) spending all my level ups on crafting stuff. You'd think this would gimp me but nope. Got along just fine. In fact, I chose my SPECIAL almost at random and encoutered no real issues. Until I wanted to build a Ppwer Armor Station at Taffington boat house and found out I needed 6 Charisma and the second rank of Local Leader for some reason.
I could keep talking about my issues with Fallout 4, but I'll stop there. MGSV is just straight up the better game. I've been playing the series MGS1 on the PS1 (which I still own, including the VR Missions expansion) and honestly, I didn't have a problem with the story. It is blatantly unfinished, but what is there is good, not the series best, but decent. The less said about FO4's story the better.
Basically it boils down to one game being as wide as an ocean and as deep as a puddle, and the other being an incredibly polished but unrealised masterpiece.
tl;dr Fallout 4 is shit at nearly everything it tries to do, occasionally reaching mediocre. MGSV has amazing gameplay but has flaws in the unfinished design and the story is a love/hate situation