Ok, I get ya
My own KSA 50S is very bland when first powered, but does become acceptable after a couple of hours. I was intimidated by it at first (it's a gift), but now I'm getting the measure of it I'm not so in awe of it now (even gets to old industry pro's like me
and I once sold the Ab Sounds portfolio!). The original one could sound 'cloudy' I found, but preamps used domestically in the Top End have come on hugely since then.
I've only ever heard one large Parasound amp and it was very good indeed. I think they were regarded as 'AV' so ignored by the snooty two-channel brigade. Others have spoken highly of other models, so well worth trying to find one
I think the Crown XLS models would be amazing for speakers like passive ATC's and maybe NS1000's, which NEED loads of power to make 'em dance to the music's tune IMO. My mate's Duetta Signatures in the years they worked properly were incredibly 'open' to what they were fed with and if yours are better made than this (and hopefully longer lasting than a mere ten years), then do look out for an early big ML amp. Hifi Dave may be able to advise on models to look out for, as the more bling they acquired, the less exalted they became, even if they became more 'commercial' as a result.
Good luck - and please report your findings, as well as other recommendations..
P.S. Don't laugh, but what about the current big Quad mono's? The 606 onwards were perfectly happy with 4 ohm loads and the basic design has been refined considerably since then I think.