Alright, going to weigh in with my 2 cents.
I'm not against some kind of defensive revision. I really, really don't think the jacks are that revision at all though, trivial as they are. Maybe folded in with some other defensive things, but I'm not sure a mine is enough to make it worth that, and they definitely should not be the primary focus as they are now. Maybe add in an AT mine with some kind of gravity-trigger in addition to the normal one, for dealing with their infantry transports along with tanks? Or do continue to try and do the uniform stuff - I don't see the Mountaineer being that difficult, although that's not uniform. I do think that the portable machine guns would help in defense as well as offense, and to be entirely honest Powder I don't see where the argument of not stretching improvement across turns comes from. Salvios has shown with the Mountain that we can work up to things across multiple turns, and I
really don't think that everything happening in one turn would somehow cause more of a shift than the same stuff happening across multiple. I'm also not sure how Abbera would "respond" to mobile machine guns or high mobility infantry with "infantry work" any more than they would increase anti-infantry ability regardless.
So, in regards to Abberan strategy, I see them blowing up the bridge as a clear indicator of two things: They expect us to attack via Harren, and they're not planning to go on the attack there for a bit. They probably mean to either double push the Savannah to get a proper foothold, or push mountains and the savannah trying to circumvent Harren altogether. I don't feel like losing territory this turn is a foregone conclusion though, depending on how Abbera's normal design worked; what let them succeed in defending the mountains, will not necessarily let them succeed on the assault side of that. That being said, it well could, and with how narrowly they took ground in the Savannah with fortification 2 I would be surprised if they could breach fortification 4 mountains - that issue is mostly one of whether we think that keeping that territory on lockdown is worth spending a revision. It's basically, do we want to use that revision on some issue that we have, or do we want to use it to make it so we basically don't have to worry about our mountains again?
So, my vote is going to be largely based on what I think Abbera's going to be doing with this turn. I think they're going to push the side lanes - they've basically tried to lock down their crossing, that's where their fortification is going to go, and the bridge blowing up is not what one does on the attack. I think their normal design will be something making an attempt to match the Charybdis - right now, that is the massive thing they can't deal with, and even with the ships they have no real answer to it once they're off the coasts. I think that their national effort is some kind of sky battleship for the same reason - and I think it didn't work all that much, since MoP implied we'd get a second revision if one side's NE sucked. Thus one of their revisions is almost certainly to that, and the other is likely going to be fixing up their normal design if it worked, or trying something else in the AA vein - anti-air gun? Although, I could also see some modification to the tank...
I am leaning towards a vote for the mountain fortification, since I think if any of what they did this turn went well, they might have enough to get past level 2 fortification, but I'm confident they won't pass level 4. I think we
could try and push the crossing this turn, depending on MoP's answer in discord about whether we can get the bridges up this turn. I expect that that'll be a no, though, so maybe defending there is the smart play. Thus, I think only pushing the Savannah, trying to get them out of there before they get in deep is what we should do. Now, what would help with that? Of what's been proposed, the mobile machine guns, the bombers, and the mountaineer work best on that. I think while they're scrambling to reach parity in the air, we can gain ground on the ground stuff, so I'm leaning towards either the mobile MGs or the Mountaineer. Of those, I honestly could go for either, but I'm slightly leaning the machine gun on the grounds that it could help in defense as well as offense. Not a solid decision and I might change my mind - the Mountaineer's experience towards a retry of the infantry uniform would be super valuable, and honestly I quite like the bomber too.
Fortify the South Peaks: (4) Powder Miner, DGR, Jilladilla, Twinwolf
Salviosi Jacks and other defensive measures: (4) Powder Miner, DGR, Taricus, Rockeater
Portable Gatling Guns: (3) NUKE9.13, Jilladilla, Twinwolf
ECR-15 'Mountaineer': (1) NUKE9.13
TBC-16 "Doomfire" Tactical Bomber: (1) Taricus
Fortify Harren (1): Rockeater