Having had a week to digest it, I think I might like almost all of the changes. The most important factor for my enjoyment is that no one hero or handful of heroes are obnoxiously prevalent. With the exception of monkey king, though his new guy popularity seems to be falling off a bit (PA and Pudka back to their rightful spots as most picked).
I feel used to the map changes now I wonder if it will be reworked more, for example the dire jungle feels very open to me and rad side seems to have more trees making it harder to ward, I don't know what I think of the new Rosh pit.
The talent trees are interesting. and I suppose they function as a buff to every hero in the game. It provides some interesting options to think about but I've found myself going for the same things most of the time. also I'd like to take the opportunity to say thank you to the left side of dragon knights tree for being just what that hero needs when he needs it in order to function as a hard carry. Thank you for saving Sir Davion.
The Lycan rework is great, he remains a strong independent wolf who needs no armor. Also it has really opened him up to a variety of item build most of which I haven't gotten to try yet, and fast armlet which I need to try again.
The new mask of madness sucks and seems useless on everyone always. Seven seconds of silence is too long. Mattling you tried it on luna one time right? what did you think of it?
so much has changed that there remains a boatload of things I'd like to try. Maybe I'll keep adding my rambling thoughts to this post as I go.