That would be too opinionated, to be honest.
Let's face it, there is a higher majority of users above that point range that really aren't super smart about the competitive meta-game. In this case, it really wouldn't work well.
But i'll just be blunt and honest here. I don't think it would work out without having some really screwed up tiers. I'll leave trachy, DT, PB, SF, Hex, and everyone else who was super involved in editing and creating the tiers ( mainly editing ) to chime in their opinions, but that kind of system isn't very likely to work out well. Meaning it would be a lot of trouble for Pokemaster that could easily go to waste. Now one last thing I'd like to mention.
To give each pokemon a fair shake, let's cut your number of three weeks into a third of that for 1 week per pokemon evaluated. Now instead of going on all 649, let's just guess that... about a half of them are completely unevolved and don't need to be tiered.
That leaves 325 pokemon to be voted on. Now if we give each pokemon a week..
That's 325 weeks of polls before the tiers are complete. There are 52 weeks in a year.
So yeah, that would be 7 years or so. Even cutting it down to like 3 days would still be like 3 years ( i think, i'm pretty tired.. ).