The new 3v3 map is awful, I'm sorry to say it but it is. You tried to hard to make it like dominion but the player community wants more 'normal' maps; maps that are not rushed in gameplay and not as compact. The whole Altar system is not a bad idea in itself but taking out individual buffs was a bad idea, although I don't find it right that the other team has vision of the altars. It's like keeping a constant eye on Baron without wards or face-checking. As for Vilemaw, the buff he gives does not go hand in hand with how much it takes to defeat him, especially since he is literally just above top lane, this makes it difficult to be discrete when taking him. There should be at least 1 brush up there at the very least, if a top jungle could be added it would be more balanced.
The old Twisted Treeline had a nice feel to it, you had time to call Mia without the enemy champion arriving at the other lane before you even hit 'enter'. This is the case in the new haunted isles map. As one of the more pressing matters it is too small, you cannot avoid the enemy for more than ten seconds at a time. I realized thats probably what you were going for but its not a system that works. This system causes the losing team to be losing at all times. Whichever team gets the upper hand early game has earned themselves a predestined victory. If one would get aced in a level one gank in the old twisted treeline he/she could simply play defensive and farm until they are on par with the other team's level. Gold was not ridiculously easy to earn either. In the new setup one altar provides every champion on that team with a buff that grants 4 gold upon kills of anykind. That stacked with Twisted Fate's passive allows for major income early on which essentially wins the game due to the fact that the more gold you possess at any given moment the more items you may buy, you may also alter your build with this gold if the need ever arises. The obelisk is also set up in a way that displeases most of the player community. If you're being pushed to your Nexus you're going to either want to heal up and get straight to it as soon as possible or get to it as soon as you respawn; either way you can no longer do that due to the wall in between fountain and the Nexus, the only way to get beyond this wall aside from 'jumping' characters is a flash and I am quite positive that players would have burned their flash trying to escape previous to their deaths.
The neutral minions are the last issue I believe I must address. As I have stated earlier taking out individual buffs in the game was a mistake, If I needed a Crest of the Ancient Lizard buff (aka 'Red Buff') for the slow I would instead have to buy a new item now. The amount of minions in the forest I believe is the same as it was before although before they were spread into a wide and even area. There is no feeling of sides on this new map therefore one cannot go into the forest to kill neutral minions feeling safe and secure knowing the enemy team should have no reason to over extend so far. My final suggestion is to bring back the old Twisted treeline, the one that the player base felt comfortable on, keeping the new map would be a good idea ( just so long as the classic Twisted treeline comes back as well), it allows for more diversity in the gameplay for all the players in the community that are not satisfied with classic.