I love Mass Effect and yeah, that Diablo loot system was already in Nioh and Stranger of Paradise, to the point where it got bloated and annoying to deal with.
You haven't really sold me on it... Maybe if it's more gorey and arcadey fun than Nioh. I felt Nioh was too hardcore for me...
Hard to say, and hard to sell. I've put about 115 hours into it but I understand if others don't like it as much.
The combat seems relatively arcadey to me. It's also a relative breeze if you simply play the game rather than plow through main missions. It's tough at first but you get over-leveled and the weapons system is really rewarding if you take advantsge of the perk system. There's also useful buffs and debuffs for combat.
It's one of those games that if you enjoy and explore the menus/systems, you'll see how many options you have available and you end up enjoying that much more.
If you plow through it, it'll probably come off as disjointed and meh.
Game is a total gem but yea, not everyone is going to enjoy it the same.