Class Balance 2nd Edition

I've been getting more and more interesting in Game Design and my pet project of designing D&d 5th edition, and i've been trying to figure out what class balance actually is. I get 3rd edition balance issues, and I've been looking into 3rd party systems alot to see how they work. I got into D&D in 3rd edition and while I hate 4th edition, I understand how it works, but more and more I find myself looking back at AD&D and marveling on how much I really like it, in particular the writing, which is far better than most 3rd edition has to offer. So, does anybody know how they can explain class balance to me in 2nd edition and how it worked, or link me to some article that does? I have played D&d since I was 7 however I am not a mathematical or mechanical person, so understanding the details of the Balance has been very hard for me, as I'd much rather focus on the fluff. So, what I am asking is
1) Class Tiers for 2nd Edition, what are they?
2) Did Marshal Classes have any advantages over non marshal classes due to some of the rules? For example, i know that concentration checks and movements were different in 2nd edition which is a big deal and Wizards had to learn each spell individually. And simultaneous actions were around did that make marshal classes much better?
3) Anything from 2nd edition that might help improve class balance or at least make things more interesting?
Thanks alot
from
EE