I realised the other day that I'm up to four tanking alts - only one of them is actually max level, but still... you'd think that I was really fond of tanking or something. I do find it a reasonably fun role to play, if nothing else because I prefer playing support roles over just doing dps, but it doesn't really come naturally to me in the same way as healing because it requires you to take point and be willing to take the lead in groups, neither of which I'm very good at. It doesn't help that impatient group members can make your job a real pain by running ahead and pulling for you, and if you prefer a slightly slower pace of play the way I do, then that's even more likely to happen.
Pet tank and I were musing about this the other day and how it always seems to be the Sentinels/Marauders who insist on jumping in first.
Exhibit A: in the centre of this screenshot we've got myself, tanking Hammer Station on my baby Juggernaut and about to charge into the next pull... except that one of the two Marauders in the group has already leapt in, and the other one is in the process of somersaulting over my head. I suppose it's something about the way the class is designed - Force Leap is fun, I won't deny that, and the way the class maintains buffs, they tend to last just long enough to encourage charging from one pull to the next to keep those buffs rolling.
Most other classes on the other hand have at least some reason to not go in before the tank. Range dps tends to simply lag a little behind due to the nature of their job, and stealth classes that want to start the pull from stealth have to spend some time manoeuvring into position, which doesn't lend itself to quick ninja pulls in quite the same way. Dps Vanguards and Guardians, while theoretically in a good position to start the pull (well-armoured melee, tempting ranged attacks, Force Leap) are probably less likely to do so because they have to prove extra hard that they are dedicated to playing dps - not tanks! - seeing how their classes have tanking specs too and they've probably been exposed to at least a little bit of peer pressure to take up tanking at some point.
Then again, maybe I'm trying to over-rationalise this and there's just something about double lightsabers that attracts hyper players with extremely short attention spans. If I had a credit for every Sentinel I've seen who bounces up and down like a loony even between trash pulls or during boss fights, I'd have a nice little sum.