The game is as hard as you make it, find casual content too easy? Do it undersized or with lower tier gear.

For a real challenge go in savage, A1 & 2 might be somewhat easy but A3 will make life hard for you, and A4 well from what i've seen it looks nuts. If your still starving for a challenge, go and do Savage Coil in 110, do FCoB in 110, SCoB in i90, BCoB in i60. Strip off most of your gear and go run Titan Ex.