What? Are you kidding me, they're great! They're a known element, a buffer between us and Everything Else out there (probably Communist Bears), they are delightfully evil in all the hammiest possible ways, and they know not to mess with us! What more could we want in neighbours?
Seriously, I was joking, but the "knows not to mess with us" thing is actually important. I invite you to look at the map.
The second biggest thing on the map is the Coltyre. We know almost nothing about them, their tech levels, their culture, and they haven't picked a fight yet. Who wants to bet they're next? I mean, "attempting to dethrone the Arthwyd" is practically a rite of passage around here. Every single other civ we've come in contact with has tried to do that at some point or another (well, except our close allies the Colryd, but then we stole their capital), and the Coltyre have been quietly growing for a while now.
Seriously, they haven't done anything but consolidate their powerbase. Proccess that. That's the sort of shit we would do. Just how much infrastructure do these guys have up their sleeves? And what have they been doing with it? Because I'm pretty sure these guys have loads of Boarfolk, and fighting Boarfolk is never fun, particularly when they have an actual civ backing them up instead of scattered barbarian tribes.