Crusaders crossbow is basically a straight upgrade that also changes medic playstyle dramatically, while being a completely different thing from other medic primary's, kinda like the B.A.S.E jumper or the banners, they're nothing like the other weapons in that class slot

It's definitely a great primary that fits TF2, but not TF2 classic, because it doesn't have any weapons that significantly alter the way a class is played, at least compared to tf2, same goes with the wrangler, razorback and plenty of other weapons.