I've given up on pick&ban matches. After organizing quite a few of those I figured it's more effort than necessary.
Let me explain a bit:
Whitelists are built with the intention of adding blocking broken weapons and having anything else up for grabs.
Unlocks are not needed for 6v6 classes, most people here have roots in 6's or have played it up to that they begin to understand that meta. Medic / Scout / Solly / Demo / Sniper are all classes that can do well whatever the situation. The problem lies with those other classes. Focus an Engineer and you already limit him.
As seen in the No-Wrangler ONC, engineers were struggling in finding a way to make themselves as useful as they were with the Wrangler.
Same thing for the pyro, spy or even heavy (GRU / FOS / Sandvich). The fact is that all pick & ban formats we tried (which went from banning 2 weapons up to banning 36 weapons, aside from the pick variants we tried next to that) weren't enjoyable for the players on both teams that played a class with an important ban.
The last problem we faced was that players were getting tired of the system. Playing fat kid / pick&ban takes so much longer than a normal PUG or mix.
Mind you, we even had the alpha version of whitelist.tf (credits to my teammate Wiethoofd) to make whitelists which were added to the server instantly.
I have more points to make but frankly I'm too stoned.
Anyway if you can make this happen I salute you, just keep in mind not all weapons and classes are equally as important to ban or pick.