Let me preface this by saying I'm a developer advocate at Asana, so it's part of my job to try to construct useful stories from this sort of information. If you don't mind me asking, what do you want to see from the API? Text formatting (i.e. the strikethrough) is a huge one that I'd like to see implemented, and there are definitely some, um, ideosyncratic parts of the API (I'm trying to be nice here), but I feel it's way better than screen scraping, which is what it sounds like you're advocating.
And as for the backend, I wouldn't call it dumb, exactly, but it was implemented in a way that would help spur early growth of the company - and it succeeded in doing that, so it wasn't a poor decision from that point of view. We really, really do know that we've outgrown it now, and are hard at work replacing it with something better. That happens at just about every company as it scales. The frontend is constantly getting faster as we adopt the rewrite, and the faster backend for the API has just entered open beta, as a matter of fact; you're welcome to try it: https://asa.na/fast-api.
Asana is listening and we've been focusing a lot on performance - it's a known problem. Hopping into Asana from external links is painful and we know it (I mean, we ourselves are extremely heavy users of Asana, so we see these things too) and are working on it. Many performance changes have already landed, and more are just around the corner, so keep an eye out for things like this to keep getting better in the near future.
And as for the backend, I wouldn't call it dumb, exactly, but it was implemented in a way that would help spur early growth of the company - and it succeeded in doing that, so it wasn't a poor decision from that point of view. We really, really do know that we've outgrown it now, and are hard at work replacing it with something better. That happens at just about every company as it scales. The frontend is constantly getting faster as we adopt the rewrite, and the faster backend for the API has just entered open beta, as a matter of fact; you're welcome to try it: https://asa.na/fast-api.