It would be great to have death animations back (or at least an option).
Death animations until they finally collapse towards the ground, then ragdoll for realistic 'floppage', body rolling down slope, etc. Any decent death animation implementation would be a huge piece of work though, if done right. Much easier and cheaper for the devs just to have them go 'AHHhhh....' and ragdoll.
I'd pay for that extra realism, though

Edit: One thing I didn't consider earlier- death animations are all well and good in a turn-based game, but how realistic would it be in a realtime game, for the guy you just fatally shot to be clutching his missing arm and moaning "Ya bastidge, ya got me!" for 3 or 4 seconds, at the same time as you're still pumping another 3-4 12 gauge rounds into his head? That's one thing that wouldn't migrate too well from the old games for that reason, methinks. The death animation would have to be unaffected by your continued actions, and there goes the realism.