Well, medics high HP should help when hes in battle with needle and reviving people. Medics also start with less ammo. It might be out of balance in some cases, but Ive recently also seen hours of plays in server in a 12 player team with 2 heavy wep, 2 fops, 1 covert, 4 engis and 3 medis which seem fine ..
But I agree to make HP equal when medpacks metric loads fast and you can heal yourself pretty fast..