I played world of grindcraft since the US beta and enjoyed it until it started to turn into a raidfest.
Six can explain it at lot better than I can but Blizzard has serious changes in the works with regards to itemization and how things are calculated in game.
The bottom line is that By the time you hit level 65 the T1 epics from Molten Core will be worth less than the blues you are seeing at 65.
If they had continued with their current itemization and calculations the stuff from Blackwing Lair and above would most likely have been better than any blue at item at 70.
Now this is nice for a few reasons in my opinion and is one of the small number of reasons I'm even considering purchasing the expansion.
1. It will allow people to switch main characters without any penalty whatsoever compared to people that have stuck with one main for all of the regular game.
2. It will seriously screw the people that thought they would have a leg up due to their heavy raiding practices.
Speaking from the perspective of a person that raided 4 nights a week for almost 2 years, I would say that having more 5/10 man content and more solo stuff would do wonders for WoW.