I think we shouldn't glance by what the salvager is being used for. So you take your salvager, go into the mining field which is radioactive by the way, hope that no xenos are coming (by the way how come salvagers are so hard to kill yet it seems xenos have no problem with taking them out), take your cargo to alpha which is not that close considering other trading routes. Now the best part comes from smuggling, for i have yet to see a junker selling their scrap in alpha ( or gamma for that matter) and not taking cardi (artifacts) back. So mind the img, corse, gmg, every lawfull, outcast/corsair (depending on what you got going) and of course every other pirate. Kinda hard to do all that with just a regular transport (not impossible though i grant you that) .
Now i do agree that the regens could be cut back, but my opinion is that it would be wrong if the salvager would be made into just another transport, easy pray for whoever desires.