I completely agree with Fluffum on this one. I play a lot of 3v3 (only few ranked games, hard to find friends who are willing to play ranked TT), and no matter what people say, there ARE champions that are just overpowered on 3v3. I know everyone has their counter, and you won't get 100% win rate with any champion, but regardless, some champions are just a lot better than others.
The way banning is now, it really does suck. I wasn't negatively impacted by it in the few ranked games that I played (mainly cuz we faced scrubs the first few games), but it's kind of scary to think of what higher ELO play would look like when you get purple team. Regardless of what Pigslord said above, being blue team with first pick/first ban will ALWAYS be an advantage in and of itself, giving you the power to pick your first core champion which you can structure a team around. Given that both lanes in 3v3 are going to be solo lanes, and you'll have one jungler (if you're doing it right), That gives you 3 very powerful positions that you can fill. And just because purple DOES get to counter-pick every champion if you trade-off picks 1 per team DOESN'T mean that blue is at a disadvantage. If blue comes up with a solid team-comp with good synergy, purple isn't just going to just be able to ruin it, unless you didn't ban the main counters to your strat. That's what bans are for, for banning out champions that you don't think your team composition can handle, or that you aren't ready as a team to play against. Just some thoughts.