Nope, no thank you. At the end of the day, MMOs are about output and to a lesser extent, survivability. All talent systems and alternate progression systems do is allow players to make sub-optimal choices. Namely because there is always ONE and ONE ALONE optimal talent choice per boss. If you're smart enough to figure it out, it just becomes tedium by changing talents for optimal output. And the downside? Well, if you run into players who can't figure it out, these under-performers get worse.

edit: We already have seen the negatives of a talent system with Cross Role. I.e., the healers who need to take esuna for a fight but don't. It's frustrating. I'd rather not deal with that and low output DPS, for example, because they don't take the talent that increases DPS substantively.