Preventing conversion can work both ways. Only people who DON'T even bother to think will be unable to figure out surgeon stopping conversion etc(and if this is the case their probably a main lobby person)
its not broken, its balanced. if maf can have 2 killing roles (possibly more) with potential of 2 killing thirds, town needs some muscle. there is only 1 night killing town, this is a good balancing role.
In case none of you ever got informed, Surgeon basically does the same thing as bodyguard and doesn't even do its job correctly, it's glitched. The creator of Surgeon later asked to change it so it would be fixed, but Lucid decided to just not do that.