Radiators may need flushing..or?

you need a good oil burner tech to service it.

who tuned the burner when it was replaced?

it could be underfired because it is out of adjustment and not burning completely or because the the boiler is sooted and not moving the heat in to the water or because parts that are worn or out of adjustment aren't causing it to atomize enough oil.

You are trying to strike a balance between how long it takes the radiation to heat up and cool off feeling the temperature variation in the space.

Steam systems take a while to warm up once the thermostat calls for them — five to ten minutes isn't unusual for the radiators to start to give off heat — but they also take a while for the radiators to stop heating after the thermostat is satisfied. This give you the wonderful even heat of steam as against the on again off again of forced air. But it also means that the boiler doesn't have to fire as often — hence fewer cycles per hour will give more comfortable and efficient results (any heating system is more efficient when it is running steadily instead of constantly turning on and off).

On systems controlled by cycles per hour — which is most modern digital thermostats — somewhere between 1 and 3 cycles per hour seems to work best.

Thermal mass. Think of cooking in a skillet: if your skillet is stamped steel it heats up quickly but cools off quickly when you turn the burner off. But it it's cast-iron, it takes a bit to heat up, but retains its heat longer after you turn off the burner. Cast-iron has more thermal mass than steel.

Your steam system is largely cast-iron, whereas scorched-air is mostly steel.

How the heck did it ever work properly set at 5 cycles per hour? Anybody? Is it possible it got reset to factory default at some point and you were not aware of it?

Honeywell should have their act together. That would be a very annoying feature for all of your configuration settings to revert to factory defaults in the event of power loss. I know my White Rodgers does not do that.

sometimes things happen that cause the firmware to factory reset like esd or an overvoltage from a nearby lightning strike or the power getting interrupted just the right way to corrupt the eeprom or someone accidentally holding the right set of buttons to trigger the reset trap.

Yeah, no, I was just musing or thinking out loud that it is probably not the case. Sorry I shared it.

Is your thermostat getting power from the 24VAC transformer? If it is only battery powered then it wouldn't be affected by power surges. Sorry if that is also obvious. Just thinking out loud again.