Totally get the speed of brew day thing. I just ran some numbers through an online calculator with various wattage and with no heat lost to the environment. Heating 7.5 gallons of water from 150°F to boiling...
1600 watts = 43 minutes
3000 watts = 23 minutes
4000 watts = 17 minutes
5500 watts = 12 minutes
So yeah, the Grainfather is going to take forever and a day to start boiling. But brew day on my 3000 watt 120v system should take about 11 minutes longer than someone with a 5500 watt 240v, assuming that I preheat my water before brew day begins, such as overnight, which is simple with an electric system.
Concerning boil vigor, different strokes I guess. I have yet to see someone's clarity suffer if they're boiling off in the range of 6-10% in an hour. You should venture over to the German Brewing forum and see if their clarity is suffering by doing a gentle boil
http://forum.germanbrewing.net/viewtopic.php?f=12&t=11&start=170
I had always thought AA extraction was a function of temperature. Not entirely sure how or why a vigorous boil would result in more extraction that a calm one. Got any links to papers or articles I can read that speak to this? Something more than a list of instructions by a well known brewer.