Getting a web framework into the standard library is something I want to get working, along with a windowing library.
Currently we need to get a stackless coroutine into the language, actors for windowing event handling, reference counting and a better escape analysis story to make the experience really nice.
This work is not scheduled for PhobosV3 but a subset such as a web client with an event loop may be.
Lately I've been working on some exception handling improvements and start on the escape analysis DFA (but not on the escape analysis itself). So the work is progressing. Stackless coroutine proposal needs editing, but it is intended to be done at the start of next year for approval process.
Indeed the GC is just a library with some helpful language hooks to make the experience nice.
If you understand how it's hooked into, it's very easy to work with. There is only one area of the language related to closure context creation that can be unexpected.
The following statement originates from Adam Wilson who is heading the PhobosV3 project, and I will second it.
The issues you have are examples of known problems that PhobosV2 has suffered under. Coroutines, for instance we would like to have in language, a proposal (me, not Adam) have already made one, but it's sitting till next year. Naming and interfaces issues are a big part of what will change in PhobosV3.
That work contributes to static analysers' data flow analysis algorithms and is very widespread, even if it's in a limited capacity.
C#, gcc, clang, and even dmd, with my fast DFA engine, utilise it.
We can't all be using Astrée, far too expensive ;)