Maybe it is because I was brought up playing 1stEd AD&D when it first came out, but after that the new owners started making it too complicated. 2nd edition had some good ideas in it I agree. But after WoC took it over everything went south IMO. Everyone could do anything, everyone could add upteen classes or prestige kits, so many options and abilities, etc. Some of the ideas for prestige class look nice but are almost a class unto themselves.
I mean how does a character focus on 5-10 kits at one time and still have time to eat supper?
The whole point of a specialized kit is the character focues on something to the exclusion of all else to BE specialized. IMO a multi class kit is already specialized (having divided there focused to work on 2 kits at once) so shouldn't have the option of a kit (or 1 kit at MOST in rare instances).
Back in the day if it was not covered in the books we made up a house rule or dice roll to cover the situation. If we wanted a new class or kit we just made it up (ol Dragon Magazine had alot of ideas on this)
Just seems like the newest editions of D&D have become powerhouse oriented in a sense.
Balance can be broken pretty easily not only with characters but with items as well. I know this is something most modders keep an eye out for, which is good.
So, BG being based on 2nd edition rules has worked pretty well, but I do and have like some of the changes and new stuff modders are working with as well to make the game even more interesting (thanks to all the modders out there).