It's a part of the main scenario questline, so people expected it to be relatively easy content to clear. We weren't expecting it to be nearly Coil-level difficulty. Those of us that did clear it obviously don't want to do it again if we don't have to, especially since there's zero reward for clearing it a second time aside from the tomes you get everywhere else. I myself use the trial roulette for some quick tomes, because until SoF came out it usually dropped me in a light farm somewhere. I don't want to do SoF again unless I'm helping someone I know through it. Personally, looking back on it and thinking about it, I think the difficulty of it may have been a check of sorts to prep us for Heavensward content, but I digress.

As far as clearing it goes, the DF probably isn't the best option. To be frank it rarely is for anything even remotely difficult (I won't even use it for ANYTHING beyond Turn 4). Your best bet is asking your FC or a Linkshell, as previously stated, or you may want to opt to put a party finder together for it. There's quite a few people that love to help new people and look for soldiery bonuses for it.