The Abyss only cares about creatures, which isn't something we care about, and it's easy to get around. It doesn't have an immediate impact on the board and is a lot for that effect.
Sydri, Galvanic Genius/Aetherflux Reservoir isn't that intriguing to me. We'd have to add a bunch of cheap spells to dig for the pieces, they're not that good separate from one another. The life gain is not the focus of the deck and would need to be built around. It's also 10 mana.