I played loads of Tribes 1 and 2, this looks cool but the F2P idea turns me off.
I rather pay for a game than pay to have an advantage over others.
Though i agree with your point, this isn't pay2win.
Way it works is the game's free, you get 2 classes soldier (spinfusor) and ranger (hitscan assault rifle, presumably to be newbie friendly). The further 10 classes can be unlocked either by tribes gold (which you can buy) or tokens, which are like xp you get from winning games/kills etc. You can also buy boosters which double your token income for a certain time i think.
It doesn't seem much like an advantage, the soldier and ranger classes are plenty capable and the others are just different. Kinda like TF2/CoD/BF classes i guess, but less balance issues since they're actively changing weapon stats throughout the beta.
You can get everything in the game just by playing, paying only unlocks stuff faster.
As jaden said, the F2P is gonna really help the numbers.