I agree it may not help, but on a 300hr+ grind to the high lvls, you really think 3-4 lvls of PL is the problem?
Ive seen you play Ashion, your really good. You saying that if someone had PLed you when you were new, even for a few lvls, you wouldn't be who you are today? I know of one person that refused to be pled, just one.
Powerleveling isn't a problem by any means, unless people absolutely depend on it whenever they level ANY job in the dunes and Qufim. What I'm talking about is powerleveling a persons very first job through say, Ronfaure and La Theine.
Those levels of soloing and early partying show you what the job is capable of, not to mention that if it's their first job, it teaches them about things like aggro distance, how fast exp is better than big exp, how your statistics stack on different mobs, et cetera.
Speeding someone through this process eliminates a lot of techniques, skill, and knowledge that could have been acquired by just playing. You are ultimately playing for them.
To answer your question, no, I wouldn't know close to what I know right now if I had been powerleveled. I wouldn't be aware of ideas like maximizing spell proc rates or optimizing the gear I swap out for TPgaining/Weaponskill. I wouldn't even be aware of aggro ranges, and I'd get my team killed.