My feeling is that this coming turn, or possibly the one after, we should build another Tower and use it for this:
@veekie made
a great post a while back that included discussion of our options. I lean towards using
Ulgu.
Honestly, I think we need two defensive towers--one for dealing with lots of weaker fliers, and one for dealing with small numbers of strong fliers. The Azyr tower, depending on how the results turn out, would fall somewhere between those. And while Azyr's effectiveness against really tough enemies is mixed, the important thing to remember is that these towers are charged from ambient magic. Making a tower that uses a wind that is rarely present at the tower's location is difficult. Azyr is really, really efficient in that case, since a tower built on top of a mountain would be bathing in Azyr, while the Ulgu tower probably gets plenty of charge from the shadows/dawn/dusk every day. The Aqshy tower
might get charge when it bathes in the sunlight? But the Chamon tower would be the hardest, because there would simply be little ambient Chamon around.
What we're likely to face in the foreseeable future is Wyvern attacks from Birdmuncha or other greenskin warbosses. Doom Divers wouldn't have the range to hit any of the towers, even if they launched from the top of one of the other mountains.
But, ultimately, I think we should have three towers for defense eventually--Azyr, Aqshy, and Ulgu (for defense)--because the Eye of Gazul has proven to be so very effective for protecting K8P.
More seriously, however, we need to work on K8P's defensibility to sappers and underground attacks. Since Boney showed how snotlings could somehow tunnel through kilometers of solid rock in a matter of hours, mountains are less of an impenetrable fortress and more of a modest obstacle to skaven and greenskins.