How about a modded campaign where there is a zerg unit that can infest a protoss Nexus. But wait, I don't mean another stupid infested protoss game, in this game the infested nexus would allow the mutation of a Zerg Hybridizer from a drone, which could utilize the Protoss DNA by spawning Hybrid Larvae which can mutate into several new hybrid units. The infested Nexus could also research upgrades for them such as mild psionic shielding, or abilities such as psionic storm.

Your idea is too general. To help the discussion you must provide more details and specifics, otherwise the topic will be useless.

I'm also moving it to General StarCraft, since it's a mix of modding, ideas and campaigns.