Also, you can use shields and other cover to block their projectiles. Although it might be a bit too mean right now as the AoE goes through shields if you're close...
And for the effects there is also meant to be ways to counteract them (right now there is just one way, a power upgrade for Logan when he uses his special). I agree its not fun to helplessly watch your character burn to death. There are more effects that make you take more damage and deal less but currently no way of telling that's what is happening so it also needs fixing.
End of ramble.