I think I must be missing something here. I have had my 1989 R100GS from new and I also had a 2002 R1150GS for three years.

The R100 has either a WP or Technoflex rear shock fitted (depending on use) and the front forks are standard. It may be antiquated but I find it handles well. On very twisty road it needs a certain technique but is as quick as most bikes of the same type including R11xxGSes and quicker than some. If you're into the GS bit and have TKC or similar tyres fitted these can be a bit of a limitation. I've often been tempted to try progressive fork springs in the hope that small potholes may be absorbed a little better.

The 1150 with it's telelever front suspension was a horror. I spent a lot of time fiddling with both front and rear preload only to conclude that the OEM suspension was real rubbish and the spring rates were completely wrong. I'm about 95kg so would have expected the preload to be a little above the middle settings but the best settings I could get was with the front on the lowest and the rear on the highest and it was still hopeless. I contemplated fitting Wilbers but sold the bike instead.

I agree the telelever does reduce the diving but then the R100 hardly has enough braking to cause the forks to dive anyway, so you just learn to ride in a different way.