Clearly you have not read back through the many pages of this post. This problem started long before IOS6. Just because YOU noticed after IOS6 doesn't mean that was the source. Just because some people cannot find the problem doesn't mean it doesn't exist.
If you read, there have been countless problems that center around connectivity. The fixes have ranged from router settings to replacing the iPad altogether. I have read at least 6 different fixes for this problem and random people reporting success and failure while trying these 6 or so things.
IMO there is more than 1 problem with the iPads and likely having to do with manufacturing date, chipsets used, bios used, maybe IOS issues, etc. The important thing to point out is that APPLE HAS NEVER TAKEN RESPONSIBILITY for this.
The simplest solution that has worked about 90% of the time is buying an Apple Airport router. I don't know why, but it must handle the protocols and handshake in some weird/secret/dumb Apple manner. I hate this solution because it is expensive, puts more $ in Apple's pockets and is sort of ridiculous to think you have to buy a router just to please i-"Devices". If you don't want to go that route (which I didn't) then you need to spend hours messing with your router. I did it and found a solution that works for ME. It doesn't mean that MY solution will fix everyone's problems.
I did NOT upgrade my IOS to 6 just for this reason. I am scared it will break it again by introducing a new problem.