I know exactly what having more power does. I've been in high end audio for decades. I have owned amps from 2 wpc to 300 wpc. Which amp to use is determined be a lot of factors, not the least which are room size and acoustics and speaker efficiency (and how much hearing loss you are willing to accept). My main HT system will rattle the windows and shake the floors in a decent sized family room on 100 wpc with room to spare. In my bedroom, for which I am looking at the Elac Debut 5s, I now have modified Pioneer BS22s and I can drive them to levels of discomfort. In the past I have used very efficient, very large, horn loaded speakers on a 5wpc tube amp and gotten very high sounds levels.
There is absolutely no need for more power if you are not driving the amp into clipping. If power output at clipping produces enough speaker output, that's all you need.A more powerful amp of same sound quality usually costs quite a bit more. I'd rather spend my amp dollars on the audio quality from say NAD or Rotel than on a Pioneer or Denon receiver.
I have had discussions with Elac US concerning amplification for the Debut speakers. They are using a 30wpc amp themselves on the Debut speakers, coincidentally the same one I have. They also are working on an integrated amp of their own, with about the same power.
Amp power needed depends on a lot of factors, and "more is better" simply isn't universally true.