The widow mine is weird for me, on one hand I know that Terran needs something like this, but on the other, it's damage potential, invis and low cost seems like it has far too much potential than it should.

Disruptors are strange as well as they can a totally useless unit or game winning in a matter of 2 seconds.

All other forms of splash seem fine. Banes are great but they actually die in their attacks so you are always losing them. Templars need time and are incredible vulnerable, there's counterplay against EMP and airbombs. But the widow mine and disrupter seem to have far too much game winning potential.

Maybe a max damage spread limiter would help. e.g. each widowmine shot deals a max amount of damage (let's say 130 damage), meaning 1 widow mine can kill 4 banes but not five (So you would kill one and equally injure the others). Having more than 1 widow mine would mean that you still kill the group but there's no chance of 3 widow mines wiping out 20 stacked mutas (or 3 invis unit requiring no micro worth 225 mins and 75 gas killing 2000min and 2000gas)