Combining this with the talk of them "liking their rides" makes me giddy. I personally think if they do it right Sisters would look awesome on bikes. But just having some updated tanks would be nice too. Since they'll be out after the "Summer of Fliers" they could very well have their own Fliers in the codex. But the Exorcist being plastic instead of the interesting plastic/metal hybrid will be nice. Some seem to think the Repressor will get an include in the codex.
Rhino - 10 models
Immolator - 6 Models
Repressor - 10 Models (Make it 12!)
Immolator (A variant with weapon sponsons instead of transport capacity would be interesting)
Bikes (I'd call them Ophanim Squads to fit the angels theme that Seraphim, Dominions started)
Exorcist (Possibly give a couple different choices of main weapon)
Land Raider Cathedral (Okay, now I'm just being silly.)