My 4g iPod Touch is the same; sometimes it'll take almost 2 minutes to load, and even after that it lags quite a bit. I've had it for 2 years now, so I'm guessing its just a bit old. Perhaps your iPad may be getting old, so take that into account. Also, if you have any apps running in the multi-tasking bar it could slow down the iPad when loading, so try to kill the apps after using them. I've noticed also that a pass-code slows down a device quite a bit (although it is not always the case) but it's worth a try to disable your pass-code.
Hope this helps.