I just vendor everything. Making money in swtor is effortless and automatic; I don't have to make efficient trades on the GTN to have more money than I can spend.

Not sniper.

If it were possible, why would anyone play marauder? "Hmm, play the character that can only DPS, or play the other character that can DPS equally well as the dedicated DPS class AND tank simply by respeccing and changing out some gear..." This is how you know it's not possible: There would be no point to marauders if it were.

First: I don't think that many professional programmers/game developers are interested in creating a straight-up torture simulator that allows you to endlessly abuse someone under your control. Second: That's the kind of thing that ends up on the news, gets parents concerned, and ultimately hurts game sales. A game based on a kid's movie is probably not a good outlet for your latent desire to torment the weak and innocent.

The robot is a more effective healer when geared but it's difficult to find gear for him. No vendors sell basic gear for droids and it's rare to find it on the market. You have to rely on quest rewards and drops. Or get the crewskills necessary to make it yourself.

What else are you going to do with your money and your companions' time? Crafting is just an optional minigame that requires minimal effort on your part and spends credits that really have no better use anyway. It takes such little effort on your part (a few mouse-clicks every few minutes) that it doesn't even have to be very fun to justify doing it imo.