Voting could make a big difference if not all people scored equal points in phase 1. For example the person getting first in the battles got only 5 points in phase one and the person getting second got 10 points from phase 1. In that case voting does decide who gets to face the master.
But just that the challenger would already be pretty much set does not mean you shouldn't vote on her/him! (or specifically, me ) Amount of upgrades can make the difference between a victory and a loss in the final battle.
I (almost) quote TORB.
But after thinking about it, I would to suggest a modify for next trials...
This time what makes the difference for challengers is, above all, battle phase (in this case, phase 2). Phase 1 was not selective, because a challenger received a score not for the quality of his work, but only to have done it.
And community vote phase (phase 3) unlikely will be decisive and able to overturn the results obtained so far. (After this, I will be kicked out from time trial by community vote...lulz...)
So, my suggestion is: to mantain the spirit of phase 1 (a proof of worthiness helpful for the community), but all challengers works should be evaluate by a jury.
How? Every challenger will be submit his work by PM to an organizer member (or to his master, why not?), and a jury will evaluate all works (without knowing who did it, just a way to mantain things...honest...)
The jury could have formed by all masters, and a master couldn't vote for his element works...
I hope I wasnt' too...intricated...