Somewhat in common with the other answers, my initial reaction is against the idea.
My difficulties start around about the question of differentiating between a clear case of "I've gone as far as I can, what else can I do?" and "Here's some junk I threw together.". If my tex macro files are anything to go by, they are a complete mess of half-hacks and "cargo cult programming" held together by the flimsiest
\ofs to ensure that nothing conflicts with anything else. I'd would love to have someone take a look at that and (gently) point out all my mistakes, but I feel that that really would be a waste of their time.
Far better would be for me to identify the weak point in my code and ask a very, very specific question on that. I could include a little context, and thereby allow for someone to say, "By the way, you can collapse those twenty
\expandafters to one
So try to identify a task in your code, say, "Here's how I do X. Is there a better way?". Then you're not asking someone to rewrite your entire code, but just to give you a helping hand along the way.
SE is optimised for short, concise answers to focussed questions. It took me a while on MathOverflow to realise that, but now that I have then my life on the SE sites is a lot more relaxed!
One more thing. You comment about different methods of learning. Absolutely, there are many different ways of learning something. However (and this is why I don't really participate in math.SE), I'm not paid to teach you (or anyone else) anything here. To properly teach something where you aren't already most of the way there, I'd have to know a lot more about your background, what you already know, more about what you're trying to achieve, and so forth. That is too much information for the amount of time I have to spend on these sites. I'm happy to help, to share what I've learnt, but to a fellow traveller, not to someone at the start of their journey.
That may read harsher than it actually is. There's a heck of a lot that one can learn just by having someone, at the crucial time, say "Go left at the crossroads.". The SE architecture is set up (it seems to me) to help us identify those crossroads and stand there saying, "Go left here.". If lots of us are standing at lots of crossroads, then that's almost as good as having a guide for the whole route.