Depends upon how much money you want to spend as it's all relative to ride quality!
If your on a budget, you could have the shock rebuilt. There are plenty of suspension tuners like Racetech who will rebuild the OEM shock for around the $400 to $500 mark. I had a rear shock rebuilt for an ST1300 with OK results.
Personally, I would stay away from Wilbers. I had one of their 4 way adjustable shocks which just didn't work well in the ST. They haven't done much R&D on the ST1300 and it showed with the problems I had with the valving. In the end, the internals were mostly Ohlins and this transformed the way it worked.
There are heaps of aftermarket shocks out there that will do the job. I'd stick with a popular brand that has good after sales service, where parts are plentiful for rebuilds/repairs etc.
I'm now a convert to Ohlins and if your doing a lot of LD 2 up riding their shocks would be worth looking at. I could recommend Frank Pons from Biketech if you go down this path.
Cheers,
Tony