I'd like to know how to do something more efficiently in VIM. Is SU the site for such questions?
Sure. If you provide a bit more detail here, we can let you know if it would be alright, just to clear up any doubt. But as long as you stick to a factual, objective, answerable question, I don't see the problem.
Just be prepared for the inevitable "this is not possible" -- if you are asking how to do something that a program simply can't do (without modifying its source, since it's open source), you'll either get silence, or an answer stating that it is impossible short of making your own fork of vim.
Try to avoid opinion-based questions when you ask, but other than that, go right ahead. No need to post it here on meta first; only do that if you are really dubious about whether it's okay.