In Ardol's plan, right now, only the Frozen Halls instances (Forge of Souls, Pit of Saron, and Halls of Reflection) would drop Emblems of Triumph (I think), and every other instance would continue to drop Conquest. This would make it much slower to gear up in Triumph, as well as not forcing people who don't like five-mans to run five-mans to get their Emblems of Frost.
A key advantage to this plan is that it keeps like-geared instance runners together, at least to some extent. People who far outgear the earlier instances will have no real reason to run them. and will be concentrated in the higher instances, hopefully with others of their gear level (although WoW players being what they are, there are going to be some undergeared players in the more demanding instances). It also gives five-man players a clear progression path, similar to if not quite as difficult/rewarding as the raid progression path.
I really like the idea. Furthermore, the Frozen Halls instances feel somewhat like Blizzard is testing the idea out, especially with Halls of Reflection. Obviously they haven't made any changes with the Emblems, but the part about more difficult, more rewarding instances accompanying each raid tier is there.
However, I don't agree with the suggestion that the current system has destroyed heroics. Yes, I do have my share of no-talking, all-business, death-squad heroics that remind me more of Wolfenstein 3D on "don't hurt me" difficulty than of how heroics used to be around BC or the beginning of Wrath, when they struck me as five-man raids.
But I'm also running many more heroics than I ever have before, on all different characters and roles, and having a blast doing so. Because of the easy gear, there are far fewer completely failed groups. Say what you want about games being too easy, I still think it's much more fun than games being too hard.
If I have a spare hour, I can sit down, log in, and queue up, and within moments be running a rewarding instance. That kind of instant gratification is something that WoW has really been missing, and it definitely enhances the game for me. It may come at the cost of overall difficulty, but I think that's a price well worth paying.