Pulling multiple mobs is not advised until you have a healer companion and can DPS the mobs on your own fast enough. As to your question, all of the ranged classes are fairly stationary in PVE. Sorcs will be all cast based, but without the benefits cover gives. If you want to be a more mobile sniper, then spec Lethality as it is more DoT based and the other two specs (especially Marksman) are more turrety. Your cover will also be the biggest asset a Sniper has in PVP because you become immune to CC and gap closers. This is definitely the best rDPS AC to have in warzones, especially in the melee heavy environment we have right now.

Marauders have the highest DPS in the game and have for quite some time. If you have experience playing melee classes in MMOs then take a shot with it if you are going for the iconic sabering of being a Jedi. As mentioned, Juggernauts are great for tanking in PVE, and can do good DPS in the right hands, but are going to be out DPSed by an equally skilled marauder by 200 or so DPS. Juggs do have great burst DPS and utility so are very good for PVP.

Sorcerers get a lightsaber but it is nothing more than cosmetic. Good DPS sorcs can put out good enough numbers in PVE, but won't be welcome in high end PVP. There are much better DPS options for PVP. Healing (or hybrid healing) as a sorc will be far more welcome in both areas of the game.

Assassins are good for both PVE and PVP. They can tank extremely well in both areas, but they have good DPS in both areas as well. The nice thing about sins is that they offer quite a bit of utility to a raid (stealth rezzing fallen players, being able to taunt for mechanics, force shroud to clear debuffs in some cases). Their DPS may be a little lower than a mara, but they would certainly be welcome in a raid. They make great node defenders in PVP because of their ability to stealth CC opposing players and overall tankiness to live through an assault until help can arrive.

I think that was all the classes you mentioned. Keep in mind, you have almost none of you true abilities for your Advanced Class yet since you just got it. Many classes take a bit of time to shine so you may not want to give up yet. Once you get used to things, it only takes about 2-3 hours to get to level 11 with a new character so you can give a few things a try and see what you like.