Hold the Line is good on paper but in reality spending 250 muni on this ability is just terrible because the planes (which make the ability so expensive) arrive very late and if the enemy decaps territory or moves out of it the planes will never arrive which means you just spend 250 munitions on nothing.
It's basically clicking the button and then hoping the enemy doesn't move for 10 seconds so the planes can be triggered. It's just too hard to pull off to make it worth it.
Might be worth going ahead and just totally reworking, then, eh?
Suggestions:
A: Far cheaper (80 muni? I'm not sure how to price something like this), planes arrive much sooner, and only affects one sector (Or one sector, and two adjacent sectors), otherwise the same.
B: Far cheaper (80 muni? I'm not sure how to price something like this, either), ability is changed to provide a large amount of DR to infantry within sectors, but have no planes. Optionally: Places a severe capture speed debuff on the sector, or even locks it down entirely as long as an infantry unit is still in the sector during the duration.
C: Cheaper, planes come much more quickly but merely suppress infantry/cause mild damage (and slow/button vehicles?), RA bonus remains. Capture speed debuff on sectors containing allied infantry.
I generally think "utility" abilities are often more interesting than pure "damage" abilities, especially if they're supposed to be almost "map-wide". it's a shame most offmaps are purely damaging abilities, I think there's more room for stuff like this. I wonder if a couple of these suggestions might be a little too strong for some of the more "interestingly" shaped cutoff territories, or Vps?
Disclaimer: These are mostly just idle thoughts on the "hold the line" theme, perhaps just buffing the ability and keeping its functionality the same would be preferred... I really haven't used the commander enough to know what it "needs".