I presume you mean the creep changes?
(I'm probably looking forward to the new PvE instances more)
Here's the link of Frelorn's announcement of the new changes.
Here're the video links of the new creep dances.
And there's been loads of discussion on the creep changes, probably best to reread the last 6 pages'links on Book 14 from the Dev Tracker.
It's nice to see weaver improvements.. (you think Song will show his face again?
) and nice to see weaver raids appearing in the 'moors the past few days.. they're very impressive looking! I think the freeps are a bit creeped out, if you'll forgive the pun. There have been some nice tactics suggested for using the Lie In Wait roots, that will be interesting.
I agree with Harm that the dances are a bit silly, but emotes will be nice to have.
Diminishing Returns is the big one... it might need tweaking to balance it.. and there's a lot of complaining from freeps (I suspect the freeps that have never played a creep before). It's perfect that the DR will only be PvP, not PvE, and it could make a substantial difference. Not so much to the zergs, because dps is the main factor there.. but in small encounters and spars it might help.
And there's been mention of BIG changes coming to things with the MoM expansion... which my guess is, might be to bring the full range of resistances to creeps, and make their stats and builds equivalent to Freeps'. Meaning we get Might, Vitality, Will, etc... Probably our trait system will be revamped. But that's a different book