I have run both a Quad 99 and a Krell KAV500 into a pair of 15” MGs as an experiment and they sound absolutely fine without any problems but you won’t, indeed, want to be turning the dial up to 11! Having too much power is almost always a better problem to have than too little.
I’d guess you’d need to think whether you’d ever find a situation where a child (or a cleaner, for example,) might interfere with the preamp volume control while the HiFi is unattended.
Separates Systems:
(1) Antipodes CX and EX, Matrix Audio X-Saber DSD, Meridian DSP7000 active speakers;
(2) Lumin D2, Cary CD-308 cdp, Quad 99 power amp, Horns 5degreeN*27 speakers;
(3) Homebrew PC with Onkyo Wavio SE200 soundcard running Daphile, Quad 44 and 405.2 into Dali Zensor 1s;
(4) Sooloos C15 plus storage, Braun A2, P1, CD3, C1 and T1 into Sonus Faber Concertos.
Integrated Home System:
Sony PS-X600, Naimnet NNT01 DAB Tuner; NS02 Server; NNP01/NNP02 room amplifiers; Netstreams switches, keypads, KEF Ci130QS/Soundlight speakers.