Riot, I had high expectations for your edit to the Twisted Treeline. That being said, you did not get anywhere near my expectations with what you did. You ruined a perfectly functioning map for a beta map, that was the first thing to worry me. Then you added in dominion elements, that made things worse. Why, for the love of all that is good on this green Earth, would you add DOMINION elements to a match type meant for tactical destruction and team fights? Sure, you can claim it adds another tactical element, but that's wrong. All it does is add another thing to potentially slow down the game by giving people something to fight over that really doesn't have much of an end effect. My third grievance is the layout of the bushes in the lanes, they've switched sides, which is confusing as hell when you first get into the game, and it really messes with some initial ganks.
Now, for the things I did like, just so that I don't seem completely against this. I like the new base layout, it is definitive and adds a certain cool look to it. I love the new monster skins, they look awesome. And finally, Vilemaw. This thing looks scarier than Baron, and he's on your 3v3 map. I love it, because it gives you an impending sense of despair before you plan to fight him.
Now, for my conclusions based off of my opinions. Overall, I dislike the update. It has far stronger negative aspects than it has positive aspects. I want to see Riot bring back the old Twisted Treeline, and use this new Twisted Treeline as a 3v3 dominion setup instead. I think this option would probaby please the most people. Until something like this happens, I'm probably going to be doing very few 3v3 matches.