[X] Regular Warriors. Following the barbaric ways of the lowlanders, the People will train large numbers of warriors to fight for the People. This will give more fighters for the People, but some will be unhappy at following the barbarian ways of the lowlands (+1 Temp Martial, -1 Legitimacy, Gain Value Quality Of Its Own)
Mass combat and formation fighting, ho!
Okay, with that out of the way, my rationale for picking this choice is that my intention is to hunker down, build fortifications, and man them to secure the settlements we still have and our supply lines, while the Cateyes do their spec ops stuff (it's guerrilla warfare, the 'little war' in Spanish, not gorilla which is an animal. It kills me in the inside whenever the latter is used).
And then, we'll wait until we've got a big enough concentration of troops that are drilled enough to take the field and not be cannonfodder, or some other opportunity presents itself. We are on the defending side, and I don't think that the boarfolk can interdict our naval routes, so we may be able to win via exhaustion. This might stretch our naval transport capacity to the limit though.
I'm seeing the option not so much as getting a random farmer and telling them to go fight with minimal training. Rather, I'm seeing it as a way to start getting drill and training masters to train large bodies of warriors and then keeping the institutional knowledge when we demobilise. Also, it may be a start to a burgeoning armaments industry. (Military-Industrial complex, ho!)
I don't have any problems with Sacred Warriors per se, though. They'd be a good elite unit to act as a firebrigade that jumps from hotspot to hotspot or as unit that can be counted on reliably to take on tougher than normal opponents or missions. It's just that the regulars will be doing most of the heavy-lifting and support so it is important that they get at least decent enough training, equipment, and leadership so they can do their jobs without inordinately heavy casualties that may make operations unsustainable. The Sacred Warriors can't be everywhere after all and there is only so much they can do.
I'd be very surprised if the boarfolk are determined enough to conquer the Merntir to the point that they'll engage in extended sieges, though. The problem is, however, do we have enough time to train them to an acceptable standard and get them to the fighting? With the construction of walls, I'm gambling on the answer being yes.