To answer your original question, this is what I've come up with:
A lot of people loved playing 3v3, and thought there weren't too many problems. Some, but these were fixable with minor changes.
Then, a few vocal idiots decided they wanted Riot to change it out to make a new feel. Some of these were probably part of the Riot team, since they have said they want TT to be less of a Summoner's Rift feel. However, did they really stop to consider what the current TT players WANTED?
So, a lot of players, like me, were playing one day, and then there appears this new map on the horizon. At first it was advertised as being the same Twisted Treeline with a few fixes/changes.
Then it was advertised as a remake of the map, with the same style of play (blatant lies), and with the fixes "everyone" wanted (more lies).
Then they advertised it as being the new way TT was "supposed" to work, putting less emphasis on Tournament-style play (SR-style), and more emphasis on running around as a team, chaotically fighting in the jungle with no strategy involved. I assume this is because most of Riot's target player base are 14-year-old preteens with daddy's credit card and no ability to analyze a situation and produce a strategic solution.
So now, instead of keeping the map/feel that LOTS of us (I don't know if I can say most, but I know it's at least thousands) wanted, Riot took away what we loved and ruined 3v3 gaming. I say this because THIS IS THE ONLY 3V3 OPTION FOR US.
Riot, when you gave us Dominion, you left Summoners Rift as a map for us to use. You didn't replace it.
WHY WOULD YOU DO THIS TO 3V3 GAMING?