Hi Lemmy, welcome to the forum!
My 2 cents:
First of all, ride the bike, it's a heavy bike and completely different from a 125. Not really a city bike in my opinion, but great for weekend trips. Saddlebags are easy to fit. (I use Oxford bags myself) There are plenyy of people who have fitted panniers. But don't expect them to fit right from the shelve.
The V11 series are or will be classic bikes so in that area you will be satisfied.
Also test ride it with your wife, not everyone is fond of the rear seating position.
I'm 1,95 myself. I'm a bit cramped, but you will get used to that. It really is a bike you'll have to modify to suit your needs. A handlebar already makes a huge difference, and you have that already I see.
When the bike is sorted properly, it's reliable and it will get you home. Moto Guzzi still suffers from a bad reputation that originates from the 80's.
Maintaining the bike is quite easy. I do most of it myself and I'm not really gifted with two right hands...
Parts are not difficult to find, a good dealer still can get you almost everything you need and there are some dealers that sell online and ship worldwide. And there are after market suppliers for lots of stuff. And, if you can't source through regurlar channels, the forum classifieds are a great source. (There is also a german V11 forum)
Good luck!