The vanilla Flame Atronachs featured sequenced flame animations that were redundant, since animation effects don't work on skinned geometry (using translation or NiFlip controllers). This is due to skinned geometries requiring a normal-map to be present in order to work. Several ways were tried to get around this, but the fancy looking versions that worked in NifSkope didn't work in-game.
So the approach has been to improve everything else, namely textures and normal-maps, UV mapping, material properties, removal of vertex-colour block and tweaking of glow-effect transition keys.

An additional fireflameparticle texture is included... it will replace that of other mods if used, but should not look out-of place and fixes the horizontal-stretch of the particle emitter.