Void mine = Lance. Blast.
That is wrong in every way imaginable. I mean... HOW?!?
Missiles... yeah, you have a point there.
If the target is behind heavy fortifications, go for an easier target or failing that webway in. Going after a fortification is a very poor risk/reward ratio most of the time.
The problem isn't that the DE need titans. It's that the DE need firepower period.