With the letters representing classes, these seem to be the popular patterns of 5-box group mix:

AAAAA
ABBBB
ABCCC
ABCCD

Xzin was one of the first with ABBBB, PriestMageMageMageMage, great for PVP apparently.

ABCCC seems better suited to PVE and maybe not all that good for PVP due to too many classes. For example PallyPriestMageMageMage.

ABCCD is another for PVE mainly with PallyPriestMageMageWarlock.

AAAAA is the current rage with ShamanShamanShamanShamanShaman, with possibly DruidDruidDruidDruidDruid a possible up and comer.

Are any other AAAAA's viable?

Will the next FOTM be an AAAAA or some other pattern?