The only hardcore component that applies to 2nd Coil is the artificial restrictions SE put on it through the turn/weekly lockout system.
One week you might 1-shot T6, 7 or 8 and the next week spend 4 or 5 hours stuck on one turn because 2 or more members of your static couldn't make it to the raid.

2nd Coil in and of itself isn't actually hard, what's hardcore is getting a competent (hopefully pleasant to deal with) group together every week (preferably the same 8 people so you can allocate loot, previously Sands and Oil before they became household items). Having to PUG for anything in FFXIV is the worst, I'm sick of dealing with people who pay more attention to their parsing program than what's actually happening on the screen. I'm also sick of having to party with people who rage and point the finger when things go wrong. Give me 2nd Coil, unrestricted, in solo queue Duty Finder, every day of the week so I can click J and be happy. I'm more than competent with Turn 6-8 but I just refuse to bother revolving my life around a dysfunctional static in the middle of the night, or joining a PUG group where my DPS and skill rotations get critiqued by a bunch of elitists. I'd rather join a practice group and help players who actually appreciate it.