Overall a good read! I feel like the author is speaking in extremes for some of the points though.
"One of the biggest myths about woofers is that 8’s and 10’s are “tighter” and “cleaner” than 15’s or 18’s. Nothing is further from the truth."
Smaller subs do sound tighter, however. It's true that all subs will move at the same frequency for each note but sometimes that note isn't played long enough for the driver to fully respond. If there's a bass hit that lasts for 1/10 of a second, a smaller sub, like a 6.5" driver will be able to respond more accurately because it will be able to accelerate faster than a large sub (like an 18" for example) Over the same time interval the larger sub may not have been able to change it's velocity (accelerate) sufficiently. It's simple physics. Why do you think you use a tweeter for highs and subs for lows. They cannot share jobs.
"So in conclusion, the only reason to use a smaller bass driver is for space, weight and potentially power considerations..."
Does everyone agree with this?
Also, one reason so many people say smaller subs are faster/cleaner etc is because of the same reason a piano sounds different than a violin. It has to do with harmonics. When you play a middle C on a piano and violin, you don't just get a frequency of 263hz (or whatever a middle C is - I think it's around this frequency). You get that note plus all the other harmonics at higher frequencies. Smaller subs have different harmonics than larger ones. Hence, they sound different when playing the same notes as larger ones. This is also one reason why people say larger subs sound "boomy."
"Your subwoofer driver does not have a conscience, and it does not perform better with one type of music over another"
I cannot agree with this. Surely some subs sound better with certain types of music that other subs. I can attest for this myself as I have had 12s, 15s, and 6.5s in my car and certainly thought some songs sounded a lot better with different subs. The 6.5s make my want to blow a load with higher frequency snappiness. And the larger subs, I found, were better with lower, longer bass notes.
Reflect your thoughts. Am I crazy?