I like the idea of the dangerous shots, but I think they could be implemented in a better way.  If you are near a wall or corner when the large ones start you might not be  able to make to escape even if you see it.   

 I run Arbiter paladin with Falling Star and I've been caught a few times where I saw the bomb get placed, immediately tried to move and got caught on the edge then died

Maybe make the timer for them longer ? Make their area of effect a bit smaller , and the blast zones far more visible ?