I understand 2 spear as a default substitution for no defense, but will it be a problem for tanks to kill them before they came close?
Keeping 2 spears in defense is a valid strategy: player doesn't give any (significant) battlepoints to the attacker, but leaves his city completely defenseless (not a problem for those who collect on time). Defeating such defense doesn't give anything, but it also doesn't cost anything - attacker simply wastes 1 min of his time. In every high-age neighborhood there are several players who use "2 spears" defense strategy. Annoying, but not a big deal.
But the implementation of minimal damage changes everything. 7 stone throwers + 1 drummer will (almost) always deal some damage to troops of
any age. In later ages, defeating such army will always give 0 battlepoints, because 1 bar of damage to the high-age attacking army costs more battlepoints than all the defensive army. There is also a good chance that throwers will kill 1 unit (depends on the composition of the attacking army, but quite possible). So, players will have possibility to set the defense that gives nothing to the attacker
and causes quite a bit of damage.
This is what will happen:
- All those who use 2 spearfighters in defense will switch to 7 throwers + 1 drummer (or 8 throwers, or any other army that uses the same exploit).
- Attackers will see that they get 0 battlepoints + damage from such armies and will start to avoid fighting it (the only thing attacker gets is a slim chance of plundering, many won't risk loosing troops for it).
- It will become widely known that such defenses deter attackers from fighting, and more players will use it as a defensive strategy. In time, we'll see 7 throwers + 1 drummer much more often than we see 2 spears now.
Therefore, implementing 1 bar minimum damage is a very bad decision.
I don't think that there is any devilish plan behind this choice. It's just (a) developers don't spend 100s of hours fighting in real game conditions and don't understand that they create new exploit and (b) developers is not of a very high opinion of the player's base and will ignore any concerns expressed by the players. I would like to be wrong with point (b), but, unfortunately, developers have demonstrated it on many occasions before.