Post by Kaitain
Even for that job you're actually better off going down to Soul Link then putting the rest into Destro, so it wouldn't be SL/SL it would be SL/Ruin.
Siphon Life won't work when tanking Leo for a couple of reasons -
(a) to hold aggro above an entire raid that is trying hard to nuke like hell for the few moments that they can before the "DPS off" warning goes up again requires you to spam Searing Pain non stop from the moment Demon Phase begins until the moment it ends. You really won't even have time cast any DoTs.
(b) With the amount of Fire Resistance the Leo tank will have you resist almost all the hits so you are full health almost all the time. Siphon Life would just overheal. When one hit does get through un-resisted it can be 10k+ (hence needing Soul Link to mitigate 20% of it) and then the healers all spam you to full health asap before the next hit. It's just not really a Siphon Life type situation.
If you wanted a build just
for tanking Leo, this would be it:http://www.wowhead.com/?talent=IZbxczIiz0xoZxx0tbhuV
Pretty strange build isn't it? :-P
You don't need Demonic Resilience cos your demon should be parked somewhere where it's not getting directly hit by Leo's fireballs (and NPC spells don't crit so that half of the talent is not needed either). All other talents are set to boost the damage of Searing Pain, skipping Destructive Reach because the threat reduction is somewhat counter-productive for tanking.
Problem with all this is that this is a really crappy build for anything else. You will do a great job at Leo, but for the rest of the raid you will struggle, and you will hate the build so much you'll likely be respeccing before every Leo fight.
In which case you can try using a standard Felguard raiding build:http://www.wowhead.com/?talent=IV0oZbxczIizzestxx0z
Which works very well on all SSC bosses (even Vashj), and is great for Leo Tanking (switch to Felhunter at Leo ofc), and also works good in arena (not 2v2 though)... bringing us back to the OP's point :-P