I checked out your commit out and found it raised the limit a bit, but not as much as expected, see comments in the PR.
I also noticed that strangely after updating to your commit and rebasing on top of the newest monogame, Depth Prepass does not seem to work any more.
Before that it would give me a decent performance boost, while now it roughly halfs my framerate with enough geometry in place.
This would indicate to me that something about the depth buffer handling has changed. Hmm.
Unrelated problem #2:
The default sponza.obj scene won't build any more because of tangent problems