I like a simple and easy to work on/fix bike also, and do not need high power, so an air cooled single or twin turns me on.
My TU 250 fits the bill, but could use more power. It does fine except for hills and into head winds at higher speeds.
Not many bikes that fit the bill these days, light, mid displacement, air cooled single or twin.
Most are water cooled, heavy, valve adjustments are done with shims and the seats suck.
The TU250 was based on the old GN250, and all they need to do is remake the gn400 as a TU400 to have a very rugged reliable easy to service do anything bike.
Instead, they came out with a new water cooled 250 twin that is 75 pounds heavier then a gn400 was, with a nasty seat.
In 1969, Triumph could build a 500 twin using no plastic that was much lighter (75 pounds) then the new 400 pound 250 twin and it even had a great seat.