PvP skills --> More exp stripped / gained; automatically first hit; etc.

PvE skills --> More exp gained / more cr gained; faster mob respawn times; etc.

Raid skills --> More exp gained from wins; no exp loss from losses; harder hits when low hp; etc.

You choose a tree a stick to it, unless you use points to reset skills. 

Gets players to play their own style.

Seems like this can be attributed to the "Character Types" (eg Dredd, Kraal, etc).

Interesting.

That way, each race and differentiate themselves, and you can also differentiate in general, by picking from the three skill categories. We could do with dependencies ("can't train skill X without skill Y"), but I think we'll survive without it for the next update of the skill system.

Trees are the long term plan at the moment though. For near term, not so much