I'm not exactly sure what all the previous problems were that had been discussed, as there is more than one possibility for a WiFi disconnect/reconnect problem. Mine has been with internet connectivity of the iPad2 tethered to the iPhone4. When the iPad comes out of sleep, the two cannot re-negotiate a full connection. The link between the two might be established, but the DHCP entries for gateway and DNS get lost and can not be re-assigned without restarting the whole connection process - which entails turning off WiFi and tethering modes on both the pad and the phone, then turning them back on again (in the proper sequence). This being with the native tethering protocols - which I have signed on and am paying for through Verizon.
I also have MiWi installed and, just yesterday, discovered the MiWi OnDemand service and installed it on both units. It's a Bluetooth operation, and is FAR MORE RELIABLE than the WiFi. Still, I need to resolve the WiFi issue so that I can use that which I'm paying for (Verizon's tethering plan, at $20.00 a month). I haven't yet investigated using Verizon's/iPhone/iPad tethering through Bluetooth yet (frankly just thought of it right now. Boy, writing this stuff out can really help the thought processes sometimes.)
So, even with iPads 4.3.3 and iPhone's 4.2.8, there still is definately a problem with all this. It isn't bad enough for me to chuck either the phone or the pad, but annoying enough for me to take the time to write about it. Hopefully there's some more recent discoveries and info by knowledgeble folks here.
Thanks for reading.