In my hundreds of ToDs/VoDs/etc I have to say that I've not noticed the loot getting any better. I've seen +4 Tomes and ubber-rings drop on normal and I've been skunked on Elite more times than I care to talk about.
If these raids are getting tougher . . . is the reward getting better? Are you giving use incentive to run content on harder levels (besides epeen which doesn't count) or are you giving us incentive to NOT run the content on harder levels?
Point blank . . . are drops getting SIGNIFICANTLY better on hard/elite for the devil raids?