I've been playing twisted treeline for about a year and a half now. I played TT both before and after the SR jungle changes which also inadvertently affected TT. Thus I feel confident in my analysis and would like to share it. I'll start by describing the pros and cons of the old map, and then analyze how the new map addressed them.
Overall, I felt that mental skills played a far greater role than mechanical skills. A team that knew how to use the map effectively could fairly easily beat a team with better mechanical skills as measured by elo. Several factors allowed this:
Dynamic and Fast paced play: The gold value of objectives, and inability of a jungler to control and snowball other lanes like in SR meant that TT snowballed fast and hard. A losing invade almost always won/lost you the game, and later fights almost always yield dragon or a tower. This high risk, fast paced gameplay was exhilarating.
Bushes and Curves- This is a dream scenario for people who buy wards. Different bushes required more than 1 ward to cover completely. Figuring out how to ward optimally was a challenge in theory crafting, and those who mastered the craft succeeded as it allowed for ambushes, lane safety, and prevention/acquisition of important objectives.
Narrow Corridors and Walls- I feel that people far exaggerated the number of viable comps especially with the existence of these things. Granted, walls did make certain champions stronger, but even non wall jumping champions could flash most walls. Narrow corridors especially allowed many champions to be strong. For example, my teammate plays anivia on TT. He builds mana and then wrecks people with well placed walls and ultimates. Lastly, wall jumping is fun and makes the aforementioned warding skills even more important.
Ambiguous objectives- This is what I feel was the most important aspect and is the main reason why I play TT. Buffs, and dragon were incredibly strong, but were always doable (although incredibly risky) at any point of the game. Learning to strike a balance between utilizing these objectives, laning, and choosing teamfights is and should be the most important skill for this map.
For example, my team likes to enjoy running double jungle. The buffs, while almost
impossible to take alone, were easily taken with two people, and with the entire
team, they could all be taken at lvl 1. We also enjoyed sneaking dragons with
certain champions with wriggles.
One critical component that allowed this was that you could enter the jungle without
exposing yourself in lane. Thus the enemy team did not know if you were farming
the top jungle, or preparing for red or a gank in the middle (unless you had wards)
The result of this setup, was constant mind games and adaptations to the opposing
Turtling- Super minions could be dragged into the fountain laser. This made it very difficult to take additional base objectives. Additionally, destroying an inhibitor prevented the winning team from obtaining the majority of farm in that lane while providing extra gold and experience to the other team via super minions.
Near impossible solo jungle- Jungle camp variance and near impossible buffs often left junglers behind unless they soaked experience from lane or were able to chain gank successfully. In certain cases, randomness would actually yield one team with greater gold. For example, if one team got mid wraiths camp and the other got golem/lizard camp, the team with the golem lizard camp got more gold and experience.
Some champions are at obvious disadvantages- Many mages, supports, and tank junglers simply couldn't compete with stronger tanky dps who had higher base stats and damage.
Art- The art is nothing short of F*CKING AMAZING. The attention to detail and overall feel is absolutely Phenomenal. Bravo
New Items/Potions- Some of the items give some weaker champions the ability to compete to tanky dps.
Vilemaw- This guy's art and animations are great.
Pace- It's really fast. There's pretty much a team fight every other minute. Turtling is pretty much gone
New Items are way too strong- While they give weaker champions some edge, they give already strong champions gamebreaking power. Prime example is singed with Blackfire Torch
Strategy- Fight mid, Fight mid, Fight mid, take a tower Fight mid, Fight mid etc...If someone is missing on the map, you know they're middle. There is almost no ambiguity or mind games involved. There are no sneaky pathways, no places to cleverly ambush, you can't sneak into vilemaw's pit, and he is too strong to attempt unless most of the enemy team is dead. All the narrow corridors, curved bushes and jumpable walls were taken away. Even wards were taken out of the game. The new map shifts the emphasis to team fighting skills and turns it into a more fight based Dominion.
Comps- Team comps weren't really fixed. Wall jumping champions are weaker, mages are slightly better off due to item and buff changes, but supports and pure tanks still don't bring enough to the table. In the 10 games I've played, the strongest tanky dps and certain mages have proven to be much stronger than teams with supports and tanks.
Overall/ TL DR- The new map, while fun, is not an adequate replacement to the old map. It completely takes away the strategy/theory crafting of the old map and replaces it with constant battles. The new map, if released as is, will attract more people, but is an utter disappointment to its already committed fanbase.
Edit: I thought I'd throw in my thoughts as to what i would do to the Old TT
Jungle- Normalize small camps, remove silver buff, replace red with blue buff, remove wraith lifesteal/wolve crits, slightly reduce jungler damage overall. Silver buff gave certain champions too much power, and red buff gives ad and tanky dps power that they dont need. Adding blue buff would allow mages to have an easier time.
Turtling- the same changes as in shadow isles
Items- I like Wooglet's cap and the ichors, i would also add some kind of mage item with armor/ap/mana regen kind of like chalice but with armor.
Another Edit: What I would change on the New TT
Top jungle: Add a path that allows you to enter the top jungle without going through lane. Add buffs/jungle to the right and left of vilemaw. Make the vilemaw wall jumpable. The top jungle needs some kind of objective to take way focus from mid lane. Currently all the objectives pre 10 minutes are mid which i find incredibly stale.
Middle: Lock the altars until lane/jungle is about level 2. The current setup forces a level one confrontation every time which feels really unnatural.
Speed shrine: Remove it, or add wards back. I don't see a need for it, and believe that it provides too much power where it isn't needed.
Blackfire Torch- remove the aoe component. Why? Because Singed