Lol this is gonna be fun when flashpoints actually require thought to go through (AKA not the first one).
Tanking in SWTOR is no joke and is MUCH more involved than in WoW.
Just to give you a little idea - in WoW, threat building is at 500% now. Meaning that every point of damage you do is equal to 5 times the threat (and that's not even counting the high-threat abilities).
In TOR, the threat modifier is set to 150% while in tanking stances. Classes like Guardians have only 2 AOE abilities (one of which is on a 12 second cooldown), absolutely NO snap threat (there's ONE whole ability that does "increased threat", which puts its threshold at 200%, but even then it's low damage), a sunder that is not spammable AND which doesn't do increased threat, no dots to keep up threat on multiple targets, etc. Seriously, I'll have to read up on the other classes, but you can't play this as you can in WoW where tanking is an afterthought (the only places where tanking ability matters in WoW is in heroics - non-heroics has trivial tanking). DPS needs to watch out what they're attacking, because getting threat back on a mob that DPS has gotten aggro on requires (from theorycrafting anyway) a full 4-6 GCDs if the absurdly long CD Taunt is down. And if you're doing that, then guess what? Your primary target has a pretty big chance of losing aggro to you.
Fun
I actually love that style of tanking (it's basically vanilla and TBC WoW tanking, where you couldn't just drop in, spam your AOEs and bam, you have instant perfect AOE tanking where NOTHING will ever get off you).
Add to that the fact that Guardians (this is what I play, so it's the class I know the most about) has a very high amount of abilities to actively use in combat (3 focus generators, about 5 to 6 focus dumpers, 3 defensive cooldowns, 2 taunts, Riposte, etc) which makes hotbars a total mess and requiring extensive use of hotkeys and combinations (I already map all of my stuff to 1 to 4 and alt-1 to 4 and I'm full at like 14!) is insane. I really, REALLY wish I could do macros in this game, because I could easily fix this and get everything easily manageable into much less buttons.... For example, I have 2 main focus builders - Sundering Strike and Strike. Sundering Strike is on a 6 second cooldown, while Strike has no cooldown. I need to be spamming the living hell out of those 2 abilities to generate Focus (at 14, I get a tanking stance that generates one focus point every 6 seconds that can be talented in the late 30s to 3 seconds) but right now they have to be on two separate buttons, which takes up a ton of bar space... If I could macro to have Sundering Strike when it's up and Strike when the Sunder is down, it would save me a LOT of bar space.