The basic reason is because SWTOR and WoW use vastly different enemy group compositions.
[...] In plainer text, it's because WoW doesn't use varied ranks in group content, doesn't use loads of enemies that exclusively use ranged attacks, and doesn't use the same degree of control effects on the tank.
I had to prevent myself from replying immediately yesterday because I probably would've come off as a raving fangirl. As it is, thank you SO much for the explanation. It was detailed enough that I feel comfortable explaining it, but clear enough that I can easily sound bite it.
Also, that it was so quick!
I would ask your mate, which companion she uses when she solo/questing (it doesn't really matter but just to start the conversation).
Whats her kill order when she solo/questing?
Get her to solo a challenging H4, pull a pack with 2 golds, 2 silvers and 4 normals. Whats her kill order?
I played with her in a trio for almost a year and talked your comment over with a mutual friend who played with the mate in question for the same amount of time, and the third-hand conclusion is 'kill order? What kill order?'
I don't think she's put that much thought into it while leveling and, as mentioned initially, I'm pretty sure she hasn't done many (if any) ancillary stuff like Heroics or FPs.
I might put the question to her if it comes up again, though, because I'm wondering if part of the issue/problem is that she simply hasn't
thought about it at all, and maybe asking the question will make her do so.