If you're being overwhelmed as Inaros, you're doing something terribly wrong. Aside from his overall tankiness, if in the off chance you do feel like you're being overwhelmed his pocket sand has plenty of range and a wide arc. His scarab swarm is also surprisingly useful.
Sandstorm already does proc! With elemental sandstorm it can actually be quite strong. However it requires its own build, which is a touch sad, but overall it is meant to be a "displace all the enemies" ability.
The extra status chance sounds like overkill to me. He can already 1-hit just about anything in the game (despite his focus being as a tank/healer)
All in all, I'm quite happy with Inaros as he is now. His only TRULY redundant ability that I feel needs to be replaced is Devourment.
Not to derail, but might I see your build? It would let me see just where you're coming from.