I think it would've been nice, especially on Council where it's obvious how to do it and it wouldn't end up being easier than non-Elite like with Protectors. I also think the TF ilvl boost could have been lower, less than half a tier, and the Elite mode wouldn't have to be such a boost either. Maybe cut both bonuses in half. That or just make it so Elite mode drops all TF gear like Ra-den, instead of Elite + TF.
It would have been nice if they could have introduced a combination. Something along the lines of - you kill it in the 'Elite' way, and you're guaranteed Thunderforged... Avoids the need for more ilevels - instead takes away some of the horrid RNG involved in getting TF items.
Elite Modes would be nice if they didn't give better loot. We personally didn't kill Protectors HC Elite after Sha of Fear HC because if was more important for us to have a few more 1-Day-RaidIDs before 5.2 was released. In the end it sucked a little bit because we lost some loot through it.
A Feat of Strength, Battlepet or Mount would be a good way to encourage people to do Elite Modes.
A nice mount for killing Sul last on Council HC, a Feat of Strength for killing at least 2 Poison Heads on Megaera HC.