I can see how you might feel that way about some of it. But I actually do not really find that to generally be the case. And plenty of it is far nicer than Mdown.
However, this is jumping into completely subjective territory; you, of course, do not have to like rst, just as I do not have to like mdown. So, I will stick with my original sentiment of wishing these services would support the thing I like :)
My syntax comment was a bit abstract, apologies about this. I'm referring to RST's strictness and how painful it is to deal with, for example, something as simple as links. I don't really care which way you bold or italicize words, really...
Yeah, this just feels subjective (which isn't bad, just not terribly helpful). I find the fine-grained control gives me more power (which I prefer to something that's simpler but less powerful).
Rst feels like a happy medium between mdown and LaTeX for me, which is actually very much how I use it. I use it in situations where I would have used LaTeX in the past (instances where mdown surely wouldn't cut it). Of course, there are some times (e.g., tables, figures and bibliographies) where LaTeX is the only sensible option, but for anything simpler, I'd still prefer the power that Rst gives me.
Additionally, I actually really like most of how Rst does URLs. It is definitely less simple than mdown, but it's so much more powerful and generalized.
However, this is jumping into completely subjective territory; you, of course, do not have to like rst, just as I do not have to like mdown. So, I will stick with my original sentiment of wishing these services would support the thing I like :)