"Jrpg-like?"
Big open world, except there's only one way forward?
"The regeneration thing put me right off. I think it's pointless having these grand WWII set pieces if your regenerating like some sort of master chief clone. It totally killed the setting for me."
Really, instaheal medikits are no better.
"The grenade system is utterly messed up (hit g and you toss a grenade... I've killed myself several times trying to pick somthing up but accidently hit g instead of f)"
Yes, blame your own incompetence on the game!
rebind rebind lol
All in all, your complaints are really silly, so I'm just going to conclude that the game just isn't FOR YOU.