Honestly, ToR kind wins as far as the leveling ssytem goes. No matter what level you were, the current area/Planet as it in that game would always take the same amount of time to complete and you would at least be one level below or above the next planet. But each planet (save for tatooine and hoth shudder) would get you leveled in the same pace as th elast one, even the level 45 to 50 ones. Too bad everything else (graphics, some glitchy issues, all characters looking the same except different skin color, The Cartel shop, the list goes on) was bad. I have 4 different maxed medium geared chars finished each at a deccent pace. I havea another whos a few levels away but this game stole my attention. ITS SOOO EFFING PRETTY. Anyway I think the system that TOR did have as far as leveling goes would be a good direction to look. Cause they had different types as well.

Im only level 30 and 13 for secondary for the soul crystal so i dont realy have an oponion yet, except for the quuesting.

Im not to far but already trying to make a second class for my dang soul crystal is becomming a hassle. theres too little to do, my GF already burned through her leves in two days on crafting alone. Leves need to give more reward for raising challenge above current level, and speedy completeion.

Fate grinding, have yet to partake but its starting to look that way. So im not sure how well that effects leveling yet.

As for SWTOR being a solo mmo yes it pretty much is that way untill max level this game seems to want you to party up more, but the general leveling idea is what i enjoyed the most abotu SWTOR