What determines strongest unit for defense?

[The Fonz]

The siege weapons defending last is a known issue since before Warlords (and is working as designed), but it will be removed for the patch.

It is also true that first stikes will throw off the claculation for the best defender, but this is not new to Warlords either.

Again, if you have a save of any other situation than the two cases above where you thing the wrong unit is defending, please post it here. Just before the attack is all we need.

I did quite a number of tests in defending cities and tiles and always the program selected the correct unit to defend, taking into account bonusses and damages. So I can't reproduce the problem right now.
I'm beginning to doubt that there is a problem, perhaps it was all imagination coming from frustration.
For now I let it go and continue enjoying the game.