That would work, sure. However, I would still prefer, thematically and gameplay-wise, that huge, slow, and bulky guns that one would never realistically train upon tiny and nimble fighter craft would just... not hit them. I'd prefer having the fighters fly a bit under or over Hellbores and other improbable weapons, giving an illusion of physical depth to the battlefield.
I mean, a small ship gets in the way of a weapon meant to deal with frigates and above, it saying "haha no I'm too tiny for this " would be a turnoff. I want those things to vaporize anything in their path that's just not made to handle it.
You can use it quite well in your favor too, it's not exclusive to the AI. Shooting a heavy mortar in the way of a fighter and one hit killing it is pretty good.
Many weapons meant to deal with frigates and above would be unaffected by the change. Chainguns, assault guns, all sorts of rapid-fire, swift tracking options would still exist and be perfectly effective against fighters. It simply means there's another consideration in which weapons you take out when not every single sawed-off howitzer is an improvised AA gun (which, currently, often end up better than the real thing.)
Yes, I'm aware you
can use it in your favor, and I do (the alternative being not using that to advantage, which is not really an alternative). That does not mean I like it. In fact, it's somewhat immersion breaking. I don't feel like I'm in a space battle making a tricky shot on a fighter wing in a chaotic battlespace when I hit something with my Hellbore/Plasma Cannon/Gauss Rifle/etc, I feel like I'm rolling a bowling ball at a bunch of pins.
Using the wrong tool for the job is currently effective. It really shouldn't be, and I don't find misusing the weapons that way to be fun, so I'd rather it wasn't.
Tiny nimble fighters don't have the armor and hull of a frigate. This is a 2D game. If there is no elevation accessible to the player, it would suck for the AI to take advantage of it.
You can actually see the fighters climb up and consequently become larger on the screen when they take off from their carriers in-game, so "elevation" currently exists in a visual manner. Players do have access to carriers and so their fighters would benefit from such a mechanic, as much as any other AI carrier & strike craft.
I don't really know what else to say. Your solution is fine enough, but given the choice between your solution and just using the quasi-3D nature (that the game already has) to stop Hellbores/Plasma Cannons/Gauss Rifles/etc from accidentally insta-gibbing everything from Talons to Tridents 80% of the time (again, with potential exceptions of things intended as meat-shields like the Mining Drone), I'd happily choose the latter every day of the week and twice on Sunday.
It's either 2D or not. I liked the fact that Star Control 2 was 2D and had strict 2D rules. I also liked the fact that Freelancer was 3D and had 3D rules. But making a 2D game where you can't hurt something with a direct shot is problematic. A 2D stage where 3D rules are randomly applied to make people miss clean shots is not going to make anyone happy.
As stated before, I'm not a fan of the random chance suggestion as written. A system with select cumbersome weapons bypass fighters to strike the vessel on the other side would not be a randomly applied 3D rule as you state.
("Strict 2D rules" aren't actually in-game. Fighters
do fly over ships in-game because they're not actually on the same plane, some missile weapons fly through friendly ships without friendly fire while others will punch a huge hole in them, and the large energy PD weapon can fire over other ships to intercept hostile targets on the other side)
I'll say it again: this way, people won't bother with dedicated PD weapons at all.
Do people not bother with dedicated PD weapons at all currently?
"At all" would be a bit of a stretch, but I've had two main flagships in my current playthrough and their plasma cannons have been doing much more heavy lifting in the PD role than the actual PD weapons. At this point those dedicated PD guns are mostly there for eye candy.