Ye, I think merging the medical roles some is a good idea. Although I've not played much medical nowadays, I did like it back when you had the paramedic, and the doctor, who would have the sub-title of surgeon, medical doctor, or...physician? And it denoted what they would be doing provided they're not needed else-where. You had nurses too, they were alright.
You can't call me a medical main now though, so my opinions with a grain of salt.
The suggested names are too sciencey though, I agree. Even if the mechanics stay the same, it'll change how the department feels, particularly as new characters come in. I don't have much of an idea what to change them to, though.