The skill tree system WILL be changing. (It's not even really a tree now, but anyway)
We have some changes we are implementing to hopefully better reward continued investment in a skill, and to formalize some of the more physical changes to a skill as you invest so that they appear in more predictable places (many skills DO get big increases to range, additional projectiles, or secondary effects at later investments - it's just hard to tell, because they aren't necessarily available at the 'next' level ), and providing some other bonuses for skills that don't already have them.
We will also be changing the structure of the layout quite a bit, and how it works.
You'll still be spending points as skills unlock, but it'll work a little differently and hopefully you'll agree it is a more rewarding system -
That won't be debuting during the beta, however.
At any rate, what you're looking at now won't be what we ship.