Maybe I'm not thinking this through right/maybe it was covered in an episode (that i missed). But I always wondered why the crew couldn't program an medical team rather than just one hologram and enroll Kes & Mr.Paris. Couldn't they request another? Perhaps with less skills+experience but one that could easily handle itself just as well if not better than the pilot of the ship. Maybe a holographic nurse could've been whipped up especially in emergencies.
Ps i seem to recall the episode Latent Image when the doctor faced a massive ethical dilemma over which crewman to save...surely a med-bay with more holographic assistants would've resolved the docs issue.