More watts or better power ?

"...Russ, I’m not saying my system is lacking and being held back, just curious about peoples thoughts on more head room vs cleaner power. The XA25 is rated at 50wpc at 4 ohms, which the Amators are. The amp is class A / AB and weighs about 50 pounds. It’s pretty beefy for a 25 watt amp..."

I believe the Pass amp is a fine unit and that even at 25wpc is producing enough power, if you are happy with it’s output. What a beefy power amp does for you is mostly in the frequency extremes. A big power amp adds weight to the music, even at low volumes, that’s what they do best. It would be a solid move up. I’m not suggesting that you are in need of more power but you are in need of the sonic change a powerful amp can supply. My LS50s sound way better with the Parasound A21 than they do with my little tube integrated and I don’t play loud. The other change you can make is better loudspeakers, that will also get you in the right direction.

P.S. You have a fine system so you'll need a big change to advance it to the next level, just saying. 

Thanks Twoleftears, as I said, my system sounds very good. I was just wondering, in my system, if upgrading to a higher watt amp could make a noticeable difference. Or at that cost, would I look at line conditioning as a similar upgrade instead? 

Regarding speaker cables, I assume that speaker cables have a lesser effect on sound quality than interconnects. And because I have to run my speaker cables down into the basement and then up on the other side of the room (20' - 25') I have not invested in high end speaker cables. If I put my amp near the speakers then I would need 20'-25' interconnects, which does not seem a better solution. 

Russ, I agree and that was my initial thought process. Does it make sense to go with more watts, having a system that sounds good now. Could I really take it to the next level with a bigger amp? Based on comments here, and my own thoughts, probably not cost effective. Like you said, the change would have to be big and it's not worth the $ at this point. I'll look at protecting my gear with isolation and conditioning. 
   PS, I sold my Parasound A21 to a friend and he's running it with a pair of Spatial Labs M3s. It sounds great, great amp. 

How about better speaker placement/room enhancement?

You're realistically only using single digit wattage, nowhere near the amp specs.

I think this article will be helpful.  Certainly relevant to your discussion title.  
https://www.primaluna-usa.com/less-power-more-bass

If you in fact need to do anything at all, consider power quality over more wattage.

Tablejockey's comment is on the money.  I just did the experiment outlined in the article with a 35 watt amp driving 86 db sensitivity speakers.  Only takes 4 watts to arrive at a 92 db level. As it turns out, for me, 92 db constant white noise at 1 meter is WAAAY louder than how I listen even given my listening position is 3-4 meters (not 1) from the speakers.