Well monogame just passes stuff to sharpdx. If you are familiar with that you can pass anything you'd like, however, the default monogame hlsl compiler does not recognize many features, so that would be the harder part to add.
Something quite a lot of us would love to see worked on, but it's a bit problematic that directX and OpenGL branches would drift apart then.
Either way, getting cbuffers and UAVs supported would be awesome @Tom @Jjagg @KonajuGames, but yeah.
If you do decide to stick to monogame there's a lot of help for shaders etc you can expect, and quite a few people here are pretty invested in gfx programming