Do high dollar mono blocks truly improve the Sound Quality over the mid tier amps

The OP is asking if higher end monos "could" be a significant sonic upgrade.

IMO absolutely yes is the only answer, but the real question is how much is the OP prepared to spend, because price is MORE OFTEN THAN NOT an indication of ultimate quality.

Example: the difference in sonic quality and price between the Deltas and the new 7 series from Soulution is vast.

One way to be sure of the pairing is to ask Wilson which amps they use when they display/demo at Munich and/or Axpona. They'd know better than anyone here how to get synergy with their speakers.

You have some very nice equipment. What do you feel is lacking in the sound it makes? Perhaps room treatment is the direction you should go at this point?

@OP Replacing your XP-27 with an XP-32 would probably be a better value improvement.

Beautiful room. The dimensions are pretty ideal. The glass walls and lack of acoustic treatments make my ears hurt. As mentioned earlier, you would be better off spending your money on improving the room acoustics before buying any new equipment. 

With as nice a system as you already have, it might make sense to look for alternatives that can be swapped in once in a while for a change of pace, rather than replacements.  Yes, there are amplifiers that might suit your taste and system more than what you already have, but, that can only be determined by a trial; I don't think anyone can make a specific suggestion that would necessarily be an improvement.  Someone mentioned Soulution; yes I think their amps sound good, but will you agree?  I think Gryphon sounds good too.

But rather than going the same high powered solid state route, perhaps you can get alternatives that you can use when you get the inch for something different?  i personally don't like most high powered tube amps, but, what about something medium powered from the tube world? I like the Synthesis Roma 98DC Special Edition at 40 wpc.  If you think you need more power, their NYC100, 175 or 200 models are very good for higher powered tube amps.  They also have terrific integrated amps like the A40 and A100 that I think are super bargains and would make nice alternatives (not necessarily replacements).  My local dealer has sold Synthesis amps to several owners of Wilson speakers who were shocked at how much better these lower-powered amps sounded than the D'Agostino, Mcintosh, Diavalet, etc. amps that were in the system.  Many bought the Synthesis amp for their bedroom system, but when they tried it in their main system, that was a surprise.