That MAY be a placebo effect, because you spent $$ and expect results.
My Sachs is just revalved and its absolutely the best suspension I have ever ridden in rocks and trail trash. In my never ending quest to get KTMs to feel decent when I rode them, the bladder conversion made no difference. IMO, the leverage on that shock during the initial travel will overcome any stiction that piston o-ring may cause to the point of it being a non-issue. Have you ever noticed the stiction of the linkage when its torqued down with a fresh set of o-rings? It seems scary stiff but makes no difference in performance. Forks are another matter because they are not progressive.
Tuners like the bladders because they make it eaiser to service the shock. Like Dave said if you have had o-ring problems there are other issues at hand.