Sorry has been using Ghosts with Lockdown and Nukes in videos on his youtube channel recently. I'm not sure if he's just posting the games he wins but so far every one I've seen he's won, against players like Bisu and Free. It seems like a more realistic strategy than I would expect.
He's essentially playing an extra-turtle style while locking down speed-shuttles and arbiters, and then sometimes EMP+nuking nexuses, or nuking cannons. The lategame speed shuttles have become really common as of late, and this seems like it's intended to counter that.
He's squeezing out an extra bit of effectiveness from his last bit of supply, like he'll be controlling one part of the map with tanks while he goes and nukes somewhere else.
While it seems like the money spent on the ghost/nukes isnt equal to the money spent on the units they directly kill with nukes or lockdown, the space & time he's controlling with them seems worth it. It's letting him get things done cheaper elsewhere. He ends up basically making himself unkillable while the protoss with many more bases wears themselves out.
There is a game where he nukes a group of carriers but that seemed more like a gamble to me, and perhaps we should ignore that?
Here's some of the videos:
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