I just installed the fallen levels and I noticed a couple of differences in the units from Myth 1.
1. Avatara walk slower in the Fallen levels v2 than in TFL
2. Avatara attack slower in the fallen levels v2 than in TFL (or alternatively the flinch time out for myrmidons is lower than it should be - or both)
Specifically, an Avatara should attack fast enough to never get hit by a myrmidon in one on one combat.
This specifically came up as I was playing Pools of Iron, because Alric should be able to kill all the myrms he fights without losing much life. Yet I was unable to do so - for a while I kept on trying, but then realized it wasn't possible on Fallen Levels v2.