3.1 will have a 24 man raid. But it's likely not going to satisfy this impossible want you've developed in your head.

Despite what you think, the EX primals and Alex Normal ARE the "midcore" content. The issue is you've learned the mechanics and if you play with other people who know the mechanics (your FC) it's "easy". That's just how raids work. Even Savage will eventually be "easy" for groups once they get the mechanics down.

The Expert dungeons are the "casual" content, for lack of a better term. EX and Alex Normal are the "challenging" content... and they were (and still are for some) challenging for awhile. There are still groups that wipe and Vote Abandon on A1 and A4. But as I said, once you become comfortable with the mechanics, even challenging content will become "easy". Your best bet at this point is to challenge Savage 1 and 2.