This suggestion pairs with my other suggestion about guns, and I'll be using similar arguments for both. Don't discredit this suggestion just because it's a PvPer complaining about non-PvP stuff. I really only play ccnet and find most PvP servers boring. I like the custom features like movecraft, but I think they can be improved.
*I will be using the word PvPer to refer to players who fight on the battlefield as infantry*
I think all movecraft is balanced (fighters might do too much natural block damage, but that's not a big problem), except the IFV and tank machine gun. IMO PvP and movecraft should be kept separate. That isn't really the case with IFVs, though. I understand that the whole point of the IFV is anti-infantry, but I think it's done poorly. It's not fair that 1 IFV can take down an entire army without any repercussions. They are completely safe while in the IFV because of periscopes. If they are sunk, which requires the other side to use movecraft, they will almost never die because they can just log out. That is not a fair game mechanic at all. 1 player shouldn't be able to destroy a 10+ player army, especially since it's not skill-based but more knowledge-based. The one solution to IFVs are cannons, so basically the ONLY solution to fighting movecraft is more movecraft, but a solution to fighting PvPers is also movecraft. See how this is an unfair game mechanic? It's kinda like one guy is in creative mode, while the other side is in survival. If one can harm the other, then they both should be allowed to harm each other. Unless movecraft is meant to be superior to PvP, which I don't think is intended or should be intended. Movecraft already has their own sieges, so they shouldn't be able to dominate both types of sieges. Tbh, the main reason why PvP happens so much at town sieges is because more players find it fun. I mean half the players that go to movecraft siege regions just run around pvping, which is entirely useless, but it's fun so they do it anyway. Basically, IFVs shouldn't be invulnerable to pvpers if they can harm them.
Solution 1: I think this is the most obvious solution, but add some form of anti-tank gun. I think it should only be able to be used against IFVs, tanks (not heavy tanks), and maybe fighters. Those are the only movecraft that can do mass damage to players. Maybe the gun could be like the gun thingy on Saigon, or the original anti-tank gun. If it's like the original anti-tank gun, then periscopes should be disabled on IFVs and tanks. Whatever the gun is, it shouldn't be able to affect heavy tanks and other crafts that don't harm PvPers, otherwise it'd ruin movecraft PvP.
Solution 2: Nerf the damage done from IFVs. I do think the damage is a bit high, but I don't think this is the best solution. It also feels more like a temporary fix than a permanent one. It doesn't really fix the problems that I stated above, so I think solution 1 is better.
Solution 3: Make IFVs require more than 1 player somehow. I don't know how this would work, but it would fix 1 player being able to destroy an army. Maybe like ACC and fighters. I also don't like this idea much, but it might help.
Solution 4: Remove IFVs. This is the most radical change, but it's probably the most fair. PvP and movecraft should be kept separate. PvPers shouldn't be able to ruin movecraft fights, and vice versa. However, IFVs currently ruin PvP fights, so removing IFVs (and the tank machine gun) fixes this. PvPers don't like it when movecrafters ruins their fights, and movecrafters didn't like it when PvPers could ruin their fights (before periscopes and when boarding happened a lot)