Just go ahead and learn the typeclass hierarchy and such-- it really is quite a useful higher level of abstraction in whatever language you choose. And it definitely will enter the mainstream (even more than is already has [Swift, Scala & C# all have monadic constructs]).
> Haskell's memory footprint is extremely hard to reason about.
And you'd probably want to also throw runtime in there as well.
I think this is relative-- it's not "extremely hard" for everyone. Also, many structured programmers found object orientation "extremely hard" but somehow the industry managed to progress through that era.
Haskell is very good at a), and not bad at all at b). With the help of the profiler it shouldn't be that hard to determine a program's bottlenecks/leaks and fix them, as with any other language.
BTW, since you mention http, I have this reading on my back burner [1] but from skimming it found that for certain payloads a haskell http server may perform better than nginx (1.4, circa 2013?), which is an impressive feat.