Having been on the wrong end of the level 40 AP it struck me, no pun intended, that the reason for this level sitting is the unholy control of 'Flames of Ninauurm'.

AP's do not want to venture into hero land until they have, at least, the icy one due to the marans being effectively immune to the weapon's damage. I then looked at some AP logs on the QHCF and noticed this:

Your iceball DISMEMBERS Homard!
Homard is DEAD!!
A Frostbrand sword glows with unholy light as it steals a piece of Homard's soul.
A piercing howl emanates from a Frostbrand sword as its hunger increases.
Your weapon howls at you and you feel able to control it better.
Your weapon is briefly outlined in unholy flames.
You feel a sudden rush of insight into Flames of Ninauurm.
You feel a sudden rush of insight into control unholy blessing

It clearly says in the echo that the flames are 'unholy' and it makes sense as the flames are Ninauurm's but the damage is not unholy and so does not work against one of your primary and most aggressive enemies because the maran power grants immunity.

AP's get the 'Hellfire' edge to make their fireballs unholy so why cant the fire control do the same?

I would bet that most APs would not feel the need to level sit pre-hero to get passed 'fire control' if were not for the fact that the control is almost useless tactically.

You could argue that it works fine on everyone else but the maran but does the spell not have a reasonably big timer and so screw you over if you are using it when the maran come to raid because your weapon cant do anything?!

I would just like to see it be unholy fire as the echo suggests and see if it changes how APs are played.

Thoughts from Immortals and AP players?

The biggest one I would say is a lot of other classes get a lot tougher after 40 while, aside from the potential to build a big weapon and learns controls, APs only have one more spell to pick up.

A second thing is that ppl start gearing more for saves around hero (when they are getting serious about things) so APs start finding a lot of their repetoire ineffective in the hero ranks.

That is what Blessing of Sedayamin is for. You can always recast the control to revert the weapon back to its base damage type, so while you might not get the super happy funtime bonus from a fire control vs maran, you aren't totally boned.

Levelsitting as an AP happens for many reasons. Getting ice control for Maran is a relatively small one compared to ABS and edges, IMO.