Interesting. I was actually, at some point, going to start a new microblister thread, but haven't had a chance to get around to it.
A couple weeks back, I took my normal 2 day cold fermented NY style dough and baked it in a gas convection oven. It was the most microblisters that I've ever seen. I chalked it up to convection (and theorized that even non convection gas and wood ovens have more air flow/convection than electric), but maybe it is about moisture.
I do know, for a fact, that Pizzatown gets microblisters on every pie, and I believe they're using gas ovens (at higher than normal temps).
Frank, at Vesta, had a bread that was heavily microblistered that he makes in a convection oven (not sure if it's gas or electric), but he said that if he makes the dough with caputo (unmalted) rather than All Trumps (malted), he doesn't get microblisters. I can't say I've never seen microblisters with Caputo, but they do seem to be rare, so I do think malt plays a role.
I've gotten microblisters with anywhere from 1 to 3 day doughs, although, since I've started my microblister quest, I've not done any same day doughs. If I had to bet money on cold fermentation, I definitely would, but, at this point, I don't think anything is certain.
I still contend there's a connection with oil. Oil definitely promotes even browning, and I don't think I've ever seen microblisters without even browning. Also, as discussed elsewhere, deep fried foods are blister city.
Craig is that a fat free bread? John, how much oil is there in that pizza?
I think I've come up with a new test. Take my regular dough in my regular (electric) oven and paint a section of the rim with oil and another section with water.