Just another opinion amongst many. I'm on my second ST11 after a 6-year run on a R1200GS. The first ST I aquired at 130000km and sold at 230000km, now it has 280000km and is still going strong. The timing belt is not a big job really and as long as the final drive spline has been properly lubed at tyre changes these bikes are unkillable.
Regarding heat, my first ST, a '93, got very hot but my latest one, a '01, doesn't. The '01 has insulation under the tupperware that the '93 never had. Worthwhile looking into if you buy an earlier model.
Also, the newer bike is an ABS-CBS model. All opinions on ABS aside, the brake hardware itself is much better (better calipers, greater brake area etc). I would definitely recommend the ABS-CBS model if available.
I test rode a ST13 when leaving the first 11, but thought it felt too 'busy' compared to the extremely relaxed nature of the 11.
As far as 'boring' is concerned, my '01 with a Penske rear unit and racetech gold valves up front is surprisingly quick through the twisties. I also ride a lot of dirt roads and tracks (a habit I aquired courtesy of my GS years) and they are quite capable as such, providing you plan your attack and don't get too silly. They are easy to pick up if you lift correctly.
You can feel assured that this bike is going to deliver you to your destination without the wheels falling off