SG can be fabulous in ET if the party is good enough to support it. Just don't try to tank ifrit since he has LP and hurts way too much. You can easily tank all the others with SW's though, and tank berz as well if your prof can remove LP's for you. Or if there is no prof you can tank him while DPSing him with crits using a DDT/DDD book. But I highly recommend a prof for dispelling valk's assumptio as well as other things to dispell. (guardians,kasa's etc etc) but how you kill them will depend on your party. You may really want to get a serious party to practice with a few times then take it into ET. You can assist in ifrit's room by staying alive and doing emergency ress incase they wipe. SG also works well in the thorn room, removing thorns by heat helps if you don't have a prof and are forced to clear some thorns for your team. FSK makes staying on a thorn easier than most melee classes. (push back due to arrow shower) After that usually gtb+pneuma should keep you on the thorn you want to kill.
Hopefully it won't turn out for you the way it did for me.