Tough content doesn't have to just be about fighting. Getting through a dungeon in 25 minutes is tough, even if the bosses are the easier part. Figuring out the strategies to optimise your run through the dungeon and to optimise your damage output on bosses is the tough part.
That said, I agree we need more tough content and some 45+ minute fights would be awesome. Since Ifrit is just a fight rather than a dungeon I'm hoping this fight is longer than the usual fights we'd had.
SE talked about company leves, I am hoping these are similar to FFXII's mark system where you'd pick up a ticket and then hunt down some challenging creature. Yoshi knows we hate standard leves so surely he has more in mind than go kill 5 marmots. The nice thing about that kind of system is it allows for open world instanced content that makes the game feel more alive.