To be honest I'm sceptic. I'd like to see that if you cross this kind of occasion in your games
DanF5771 posted a drill IV, flanking II ironclad defending instead of a destroyer against an attacking destroyer with drill IV. If the destroyer were to defend, the odds were close to 50%. The ironclad had < 20% odds.
By the way, first strikes ARE factored into combat odds and have been for some time...that was more a vanilla problem (early on).
The game adds a flat value for first strikes (and half of that for first strike chances), and this can easily make it defend with guys who have markedly worse odds.
@OP: The reason that great generals defend is bad coding. That high combat and CR great generals defend instead of alternatives is a programming judgment error - these units are far more valuable than other units and won't have much better odds. The game should not defend with them.
If the game (properly) allows caravels to defend loaded galleons, it can (and should) allow other units to defend ahead of generals. But it doesn't, which limits great generals to super medics or specialized units like high combat + march + blitz mounted (which still won't tend to defend on most terrain or vs most units). I wish the game treated this better, because other than the medic settling seems far and away the obvious choice...and it shouldn't be like that, there should be more situations where either is a valid choice depending on what you want to do.
That's not how it works. You or the AI can't just choose which units to attack, they always go against the one who has the best chance of winning against them. If they're going after the Cats before the Axemen than it means your Axemen are wounded.
Without any spears in the stack, chariots would target the cats directly. With charge, they'd even have winning odds. HAs get a bonus vs cats and therefore would draw the axes first (though very favorably with shock).