my opinion of the original question is no. as long as it does not harm the equipment because of impedance as already mentioned. sometimes people prefer something for reasons others dont understand. lots of guitarists must have a double stack. they do not need all of its capabilities, but they need it to be what they envision themselves as. (like the guy with the porsche who never goes over 65mph) maybe the impedance plot of a 8 ohm 4x12 versus a 8 ohm 1x12 with the same drivers may be different and affecting the amp in ways we are not aware of. i am glad we have lots of speaker choices so everyone can have their own "sound" johnny a.
that's not a bad point, although most marshall gurus will point out the real tone difference comes from 16 ohm or 8 ohm load, not the number of drivers in terms of an impedance plot.
In terms of the analogy of the porche, it only goes so far when talking about tube amps. With a 1000 watt SS amp it holds more water. I use 650 in my standard configuration, but most of the time i'm "driving 55" - the thing is, the amp sounds the same outside of any sonic differences as the cones get pushed.
With a tube amp, "driving 55" just doesn't cut it. Power tubes don't start to "do their thing" until you reach a certain gain/volume level. Most guys I know who use half or full stacks of 4x12 cabs and 50 or 100 watt heads rely on stomp boxes to try to emulate the tone of a cranked tube amp when playing at a more reasonable volume. This totally defeats the purpose of using a tube guitar amp in the first place. Perhaps a better analogy would be that they're using a musclecar with a racing camshaft and not ever hitting the RPMs needed to make that cam work properly. The result is subpar performance. Tube guitar amps are meant to be "drilled". This isn't all theory. I've played with guys where one has a 100 watt half stack and the other has a 15 watt 1x12 combo. Guess who had the better tone at an appropriate volume?
I'd reiterate the point about the "full sound" as I feel it's so important. Having done a lot of sound as a soundman, and having been more or less in charge of a band I played in getting a good mix, it's like pulling teeth to get a GP to agree to cut the lows on their amp. I think at this point most bass players understand that the tone that sounds "awesome" when you play by yourself just doesn't cut it live as all the instruments step on each other sonically. I can't tell you the number of gigs I've played or mixed with a GP unwilling to change their tone settings where the only recourse was to EQ my bass amp to have very little lows and lots of mids in order to fit inside the "smiley face" EQ of the guitar(s), and/or cutting almost all the lows to the guitars in the FOH to and praying that they didn't turn up so loud that they overpowered the sound coming out of the mains.
Last but not least, most of those tube amps are direct descendants of the tom walker RCA circuit "fender tone stack" (even marshalls, wher jim admitted he reverse engineered a bassman's preamp). As such, nominal "flat is 2-10-2 B-M-T. Goosing the bass and treble up to 10 just doesn't help. Once again I implore folk (bass and guitar players) to listen to the individual tracks on their favorite albums and see(hear) just how strange the tone is on each instrument. The net result sounds great, whereas if every instrument sounded "awesome" the whole thing would sound like mud. We're lucky these days as on youtube you can find tons of isolated tracks. They can be real eye/ear openers.
not flaming anybody - heck generally no one's ever told them this stuff. Just pointing out that sometimes you need to think "outside the box" unlearn some old habits, and find out just how your gear works.