The issue Ive seen historically with MMOs that use tree limitations is that out of the potential number of combinations, there arises a very small number of optimized builds most of the players end up playing due to the severe restriction placing one enhancement into the third tree resulting in all other trees closing down. Once this happens, the number of possible FURTHER combinations for that toon just decreased dramatically.
With the combinations already being limited by class split, and capped by the number of possible points total that can be taken, the three tree limit isnt necessary, and even players who have spent half their points and in 3 or more trees experience a dilema for what they can still take, which is a good thing.
I know when game designers did their game correctly when Ive chosen half of my options and its still a huge internal debate as for which to pick using the rest of myu points. It becomes a non debate when there are further unnecessary limitations present in the system. Example: You already put points into Arcane Archer, Tempest, and Half Elf Racial, At this point, the only real decision left is to allocate more points up the same trees, because you just boxed yourself in. This creates a situation where because of that limitation, there is a small number of 3 tree combinations that are more powerful than the rest for specific roles. Once the optimizers hammer out what those combinations are, plan on seeing alot of them, with small veriations.
I am interested in hearing how the team plans to solve what I stated above if you choose to stick with the three tree limitation, or if that limitation will be relaxed.