I am a first time BMW owner and I realized there would be some issues going in with a bike as complex as the GT. To be honest, my old "jap bikes" have been around for quite a while and have never seen the inside of a shop.
But bikes are all a lot more complicated now, a techno-tourer bike like the GT would be at the top of the heap. I certainly know there are lots of old boxers out there that have never seen the inside of a shop either.
I personally made the jump because of the experience of actually riding the bike. I always liked it, and when a deal came up, I decided to go for it. I didn't "want a BMW" or some sort of image it projects, or whatever. Just liked the bike. Willing to put up with some of the "issues" due to complexity (computer hookups, CANBUS, fuel injection, etc.).
So, I guess the short answer is "get what you want". There are always some practical considerations, but most things can be worked around if you really want it. You are getting a motorcycle after all, not investment property. You can "makes more sense" yourself down to a Civic if you keep working all the angles.
If you are still comfortable riding after your long layoff, get a ride on the candidates if possible (otherwise, take a MSF riding course then the test rides). Think about what you want to do with the bike. A GT probably isn't the best for intercity commuting, track days or off-road racing (although all have probably been done!
). Some retro and cruiser bikes aren't the best on twisty roads or for long distance rides.
You can probably find an old GS1100 to start on again too, as far as that goes! Great bike, had one of those as well (82 E model, red). Riding something new now will make it seem like a bus though!