I think what struck me in Portia and aeh's responses was their differentiating between letting a child avoid hard (but essential) stuff, vs. letting them run ahead in areas they love, without requiring them to follow the same linear script to get there as everyone else.
For mine, I have found the latter is essential - to keep them motivated and engaged, I need to feed them the conceptual stuff at the level of their appetite, and that can sometimes leap far ahead of their automaticity and skills in the daily grind. And when we do the fun stuff, I may be providing huge scaffolding on their weak areas so they don't get in the way. I don't want to hold them back to the level of their weakest skill. But yes, madeinuk, because we live in the same anti-acceleration world as Can2k, with DS I angst every word of your post, daily (nice verb, huh?)
However, letting them fly in their strengths is quite different from letting them avoid their weaknesses, which is surely a recipe for long-term disaster. And DD and I have spent the last year and a half in the reality Portia so well-describes above: if you have to do all the nasty stuff at home because they won't do it at school, that's really hard on your relationship with your kid. (But DD completed vision therapy this week! YYYYYEEEEEEEEAAAAAAHHHHHHHH!!!!!!!!!!! I There are no words to say how happy I am to not have to make her do that any more).
So here in asynchronous land, I would never try to put the brakes on the fast-moving pieces to match the speed of the slow ones. But I would pay close attention to the slow ones to make sure they are developing at a level and speed that is reasonable and appropriate for this particular child, in this particular skill area. (says I. this is why I don't homeschool DS: we'd do math and physics all day long, and forget about language arts and social sciences for years on end. and I'm an artsy - but it's just so much fun to watch that mind fly when we let it chase antelopes.)