At this point, I'm hiding from a second treant siege while I prepare ways to prevent buildingdestroyers from wrecking 120 grates each time they show up, as well as thinking about ways to actually kill the things. I'm thinking of lining my whole entryway with upright spike traps for emergency use.
You should use ballistas, take screenshots, and give me some to use in the OP . Glad you're enjoying it.
I would try out siege engines, but the version of CatSplosion I'm using doesn't allow cats to use siege engineers. Also, the killing field of my defensive setup works across 6 z-levels and isn't very big on any one of those, so screenshots wouldn't be too impressive for me.
I've now encountered werewolves, and found them stupidly easy. My sentry animals detected them with enough time for me to get my markscats in place, and then the 'wolves got driven away before they got through the third switchback. I only killed 3 or 4 of them, but they weren't actually a threat. I think the only thing I actually have difficulty with is the treants; with a mooded legendary+5 bonecarver, mooded bowyer, and champion markscats, my soldiers can hit pretty much no matter what, and at the top of that long slope behind fortifications enemy marksmen can't hit them very well at all. The problem with treants is that damblock tag, which prevents my cats from doing more than chip damage which the treants mostly heal as quick as it's done. I don't think I saw more than 2 light grey wounds on any of them before they left at season's end.
So, now I'm building large numbers of steel spikes and mechanisms so I can have a last-resort "murder everything" lever. I've already linked every grate in my entryway to a different lever, so I won't lose them all to the next treant siege I let in, but I'm also probably going to turn up my popcap a bit so I can get some meleers sparring. Cats are size 3, but with sufficient training and suitable equipment, they shall prevail, even against the mighty treants and giants!
...I just find the cat mod hilarious, especially with other mods on that already increase difficulty. The concept of dwarves killing stuff thrice their size is cool, but they're humanoid and mostly just little people. The concept of a sapient housecat killing stuff five times their size, or more? Totally awesome.