MDL-12403 was a step forwards, and thank you very much to Dan for tackling it.
But, it was only one step, and we need more, which is why MDL-41924 was created.
Regarding it being very slow Russell Smith did a lot of good work at MDL-40579, but ran out of time before he could finish. It would be great if he could get some more time, or someone else can finish it. (I am not going to have any time for the foreseeable future.)