Now I’m saying this rather broadly and including most aspects of things people would generally consider aspects of coils raid design that fell away in Gordias and never really returned (just as a side note here I did coils on patch you don’t have to tell me that jobs are extremely different now and a lot of transition would be messy)
For me there are three things coils raids did that they did better than anything after it
1) pre fight mechanics- coils raids actually felt like what you would imagine when you think of raids, they had mini bosses, they had trash packs, they had hidden treasure chests, less so in final coil but the raids felt like they had a real sense of progression in physical space, in eden and omega specifically you just feel like you are being teleported around randomly but in coils you feel like you are making real descent into the depths of the coils; this is somewhat made both better and worse by T3 but I’m willing to overlook T3, however for most other fights it really adds to their scale. Think something like turn 11, the giant dalamud replica you have to traverse to get to the boss gives the boss a far larger scale than say just teleporting into shadowkeepers arena that looks like it’s in some random ruins in Lakeland
2) interesting and different mechanics- now you can make the argument that every mechanic is a new mechanic in the games first raid tier (I’m not counting original rivenroad here) but coils has a lot of mechanics we have never seen again and mechanics that do not fall into the traditional mechanical sense we know today, think mechanics like turn 11’s boss hitbox being a death field forcing you to rotate around him, or T6 leaf storm these mechanics are just so different to the dance we have today and they rarely felt like they got as boring as the raids we have now
3) adds phases- what is it about post HW design that means square cannot make good adds phases anymore, coils had fantastic adds phases and they were all Meaningful with unique mechanics that made them worth doing
So yeah coils just feels so different to anything after it and I feel like 14 is missing that kind of uniqueness in design, however I know coils completion on patch is rare these days so most people probably never experienced it and like our current system, I just think it could add some more diversity to 14 raiding to have more T1/2/6/7/8/11/12 style fights we really see nothing of these days