I have been test one leonozzle during 3 days, ABS without fan, and the results are really marvelous.
Just be careful which cased thermistors you get - most cheap ones use epoxy (rated at 125°C) as a filler and ahesive.
Now of course, the thermistor’s casing will have its own thermal inertia, but since it’s not even 3mm across and well-coupled to the block, i don’t see an issue with lag and such. At the very least, it’s not going to perform worse than a thermistor without any thermal interface material (which is the typical setup in basically any hotend right now).
Using an offset would compensate for the higher thermal resistance would it not? If it doesn’t vary much between individual thermistors of the same model/type that is.