Is there such a thing as too much power?

The brand names of the amps would be helpful and perhaps significant.

Depends on the quality of your amp.

Answering your title question...NO!  You can never, ever,ever have too much power!!  You just have to be careful to never overcrank the volume control.  Always keep your system well fed! (quality and quantity)

OP seems to imply that an amplifier's contribution to SQ is theoretically solely based on watts and not circuit design and a bazillion other factors.

This discussion often becomes an "all-other-things-being-equal" hypothetical discussion.  If nothing else is adversely affected by increasing power, then it probably doesn't hurt to have more power in reserve. 

But, depending on how loud one listens to music, the efficiency of the speakers, and the acoustical environment, having a big reserve of power may not increase sound quality.

Also, being able to deliver a lot of power means that the amp has to be built specifically for that priority, which typically means using a lot of output devices in parallel.  There are some people who say that using multiple tubes or transistors degrades the sound--simpler is purer.

Also, some of the higher output transistors or tubes may not be the best sounding.  I have heard tube amps that can be made to run on different tube types, and I usually end up preferring the lower output tube types (assuming reasonably high efficiency speakers).

Among both tube amps and solid state amps, most of my favorites are low-powered amps.  I like the sound of the two First Watt solid state amps I've heard more I like many ultra expensive high-powered solid state amps (most sound lifeless when playing at modest volume), and I MUCH prefer low-powered tube amps to high-powered ones.  I have fairly high efficiency speakers (99 db/w), and they really sound best with either low-powered push/pull or single-ended triode amps.