Default General Tactics and Strategy
This is a particularly frustrating situation because you may have done all the hard work of preparing, scouting, building up army for days but you could lose it all in a flash. You could have forgotten that you were attacking, you receive a phone call right before you're about to land or your connection simply dropped. If you're a lower level player who lose his entire army that you have been building for days or even weeks, it's an incredibly disheartening situation, at worst it could cause a player to leave the game completely, at best it turns them off about the game which may cause them to be less active and less likely to refer to their friends.
However I see the real challenges for the developers for this feature is just how in-depth the battle tactics can be altered. If it's a simple tweak of being able to set the default army command from "Forward" to "Wait", it would certainly provide a big help in most occasion, but it will not help all situations.
The situations where some problems may arise is that if the target has army as well as traps and turrets. In which case even if the player defeats all troops from the target the battle will continue to a draw.
I'm not sure what exactly the best method would be to implement this feature, but I am positive that the vast majority of players would welcome some form of editable default strategy. Please feel free to suggest how you think Haypi can add this feature.