Universal ammo is fine, managing inventories is definitely not something I enjoy.
i thought universal ammo was fine when i first heard about it being implemented in DX: Invisible War. i argued that it gave the player more choice in what weapons to use and so forth.
then i got the game and played it. the first time i ran out of ammo, was the moment i realised that i hated it. in survival horror titles there is a kind of joy in running out of your shotgun ammo and falling back to your pistol. that moment is a fun, scary, thing that happens.
not being able to just stick to a single gun encourages experimentation with others too.
i don't know how they're handling it exactly, and i'm not going to freak out yet, but universal ammo as previously implemented in other titles is not something that i think would work will with Dead Space 3.
if i pick up some resource and then get to choose what ammo to turn it into, and cannot convert it back afterwards, i am fine with it (as the gun powders in RE3 worked). if it's like Invisible War, it's a terrible idea for a horror game, imho.