The bike prior to my 09 Wee was a 2000 R1150GS.
Actual on road performance is very close to the same.
The Wee does everything the GS did, the only downside is a little less ground clearance.
In Australia the Wee is around 2.5 times cheaper than a GS.
From my own personal experience the servicing and repair costs are at least 40% cheaper to do on the Wee.
And the Wee is so much more reliable than the GS ever was.
Shaft versus chain is a no brainer as far as I'm concerned [BMW shaft drives in more recent years have become unreliable].
The option to change ratios from road biased use to more dirt oriented [say if you are doing an outback/bush trip for a week or two] needs by changing the front sprocket is a big advantage.
35,000km+ out of a chain and sprockets these days is not uncommon on modern bikes so it is cheap compared to blowing a shaft drive [it cost me $1500 just to get the shaft bearings done on my GS].
Buy a Wee, lift the suspension a bit and add a bash plate and crash bars and it will do everything the GS does while leaving you with a bucket of spare money.
This is why they make different bikes, because we all experience things differently and have different preferences.
I owned an R1150GS for 3 years and an '05 Strom for one, throwing in a 955i Tiger for 5 years for good measure.d
I'm not going to say you don't know what you're talking about but I will say my experience was different.
On road performance was not all that similar for me. I much prefer the relaxed cadence of the R1150.
I also prefer the more fully developed aspects of the R1150 as a package, luggage keyed to ignition key, heavy duty alternator, much better suspension and brakes.
I did not experience reliability problems with any of the bikes.
Service costs for me were very similar if done by dealers and done by the book
Obviously i didn't think the wee was that bad because i bought one. I also still have a BMW RT to keep my hand in there. All bikes are good, just a matter of figuring out what you want from them and where the strengths and weaknesses lie.