I agree that, on occassion, amplified instruments can be unneccessarily loud but when you're playing as part of a band you do need to be heard over the sound of the drum kit and whatever else is in your line up.
Some landlords and event organisers don't always realise this and, whilst always willing to oblige where possible, the accoustic sound of a drum kit is the very lowest starting point above which the levels of the other instrumentation and vocals must be set.
If it's still too loud, they've booked the wrong act!

As far as the debate of accoustic over electric, I'm with the "whatever's right for the job" group although I'm always happiest playing my accoustic unplugged. I spent quite a lot of cash trying to acheive that "unplugged" amplified sound and I'm almost there but............