[AreaOfEffect]

Both are WAD. (Working As Designed)

1) Is most likely the result of the enemy not producing sufficient threat. Mages won't use gems unless the opposing army is large enough. It isn't perfect, but it helps keep your mages from wasting spells on a casting of Call of Winds.

2) Attacking rear has some mechanic which I'm not entirely familiar with. Think of it as attack flank rather then attack rear.