last year i used 3 different yeasts for my (warm-fermented) lagers, and S-23 was my least favorite. it improved the most with time, after about 6+ months in the keg is was finally on par with the others. just another anecdote to back up your claim of improvement with time. also, this is why i'm only using 34/70 this year - it was the one that tasted best, fastest.Used S-23 yeast.
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My last dozen or so pints were marginally improved over those I had 3-4 weeks post packaging.