Missile troop order/protection questions

[Salamander8]

Thanks for the replies.

I usually have multiple blocks of melee troops set up across the whole of front the set up area to keep enemies from infiltrating through the melee to my casters and archers, but wanted to see if there were other ways to protect them. Fliers are more problematic in general than fast ground pounders as they can bypass the flank melee blocks.