I think the changes you cited (less damage due to high precision use of low yield weapons) make it on balance more likely they'll be used.
The real barrier to nuke use is gaining entry to the club. U235 enrichment, Pu239 synthesis, implosion, initiators, etc. In contrast, the entry barrier to precision delivery is small and diminishing.
If you're new in town (IN, PK, NK), your noob inefficient, unoptimized weapons can be really effective if precisely delivered. And it doesn't necessarily mean ballistic delivery. Moves the "unthinkable" threshold downward. It's worrisome.
Suppose some little country wants to start working with U and Pu. So, they set up a building, get it some utilities, surround it with some security, and then go shopping for a long list of lab supplies and equipment.
Then, likely, presto, bingo, the intel agencies of the more advanced countries will notice what is going on inside the building just from what is on the purchase orders going outside the building. Then have some drones and/or satellites fly over the building with some neutron or gamma ray detectors or some such. Then have a little chat with the leaders of that little country.
I'm not sure it would be easy to hide such activities now.
And if they do get some fissionable materials, then they would have to test a bomb, and can't hide that.
I have to believe that the "more likely to use them" is offset (I hope entirely) by the taboo of deciding to do so. If deciding to use a nuclear weapon is an open invitation for retaliation in kind, then you would expect the established players in the nuclear power game to shut it down with extreme prejudice for exactly that reason.
A smaller opening volley doesn't feel like any increased incentive to initiate said volley.
It's assured destruction. The degree and ferocity of the conventional military response to any state which opens with a small scale nuclear attack would be unlike any wars to date.
You do it and you'll get to watch the US, China and Russia briefly join forces and annihilate your infrastructure with extreme prejudice - with options to use their arsenals if anyone suspects you'll try to while this is happening.
I didn't understand the last paragraph. What you said makes sense, and the fact that countries like IN, PK, NK don't have access to tactical/precision nuclear armaments makes it less likely that they will use them, doesn't it? Because setting off a megaton device is clearly a sign for the commencement of nuclear war and certain MAD.
And sorry, I see I wasn't clear about the precision delivery aspect.
While newer members of the nuclear club may not have the greatest in precision delivery, that capability is almost completely a matter of electronic technology. Which means it's getting easier and cheaper in the same way that our cheap smartphones eclipse yesterday's mega$ supercomputers. I'm sure IN is already there, probably PK as well. NK, not so much. Yet.
That in turn makes unoptimized weapons with only say, 5kT yield very useful. Such "tiny" yields diminish the horror factor associated with using nukes. 5kT is way more "imaginable" - it's only 250 truckloads of TNT (single big rig load of 40,000 lbs).
In short, precision delivery makes low yield (cheap) bombs useful. That diminishes the restraint underpinning MAD.
PK is working on developing small tactical nukes to use against massed Indian armor, following...wait for it...NATO tactical first-use doctrine in the 1980s in Europe.
I think the changes you cited (less damage due to high precision use of low yield weapons) make it on balance more likely they'll be used.
The real barrier to nuke use is gaining entry to the club. U235 enrichment, Pu239 synthesis, implosion, initiators, etc. In contrast, the entry barrier to precision delivery is small and diminishing.
If you're new in town (IN, PK, NK), your noob inefficient, unoptimized weapons can be really effective if precisely delivered. And it doesn't necessarily mean ballistic delivery. Moves the "unthinkable" threshold downward. It's worrisome.