OK, so I don't think this is necessary to make people be scared of cloaked (or burrowed) units, I don't really think a Zerg should be forced to rush a Lair to be able to detect, of course you can use Spores but you will have to use so many that making a Lair would be the better choice.
Also, saccing cheap units isn't always an option for several possible reasons, for example:
The place where the Widow Mines Lay burrowed might be guarded by Marines or other units.
It might be really hard to know where the mines are, especially because they will in many cases move after being deployed.
And let's be honest, it can be kind of hard to expect the Widow Mines, especially if they are in random spots before you really got your mobile Detection started.
And one of the most annoying things is the fact that Hellions and Widow Mines have the exact same tech, so if you scout, say, a Factory with a Reactor-Addon, you will be forced to get detection, and also be ready for Hellions, you can't know which one it is.
As a Hellion defence you might go for Queens, but then if he comes with the mines, they will most likely CRUSH the Queens with their Amazing main target damage.
And if you go for a Lair or Spores, it'll make your Queen Production worse.
And it'll still be almost impossible to harass a Terran, if you take Mutas for example, their strength is their Mobility, bringing an Overseer just to kill mines would be silly.
Also, one mine kills one muta, TOTALLY worth the trade even without the splash
The unit is good in EVERY single way, it needs a nerf in some way.