Problem 1
GLA heavy rocket artillery is ineffective against defenses, because their missiles are often shot down before reaching the target.
Consequently, GLA players have either to rely on light artillery, which is just not possible in certain situations (due to minor range/AoE and poor pathfinding), or to build ridiculously large numbers of heavy artillery (in order to deliver at least some rockets to the target).
Building heavy artillery en masse stalls your warfactory, is expensive and extremely risky, because its quite easy to conter large numbers of artillery while they pummel on defenses, and almost impossible to protect them.
Solution
There are certainly many ways to solve this dilemma (like reducing price/buildtime of heavy rocket artillery) but they would inevitably make heavy rocket artillery even more effective in their other roles (against tanks and buildings) which isn't desirable.
Enought talk. My proposal is to introduce a second firing mode, with the same RoF, same damage, same AoE, but 2 times the range and a scatter equal to half the initial range (therefore, the maximum theoretical range would be 2.5 times the original range).
The scatter- effect would render single long-range attacks almost useless, but the additional range would make the use of heavy artillery against defense-walls viable (because you could protect them better), although the overall time to crack the defenses would probably increase.
1vs1 balance wouldnt be affected at all, because those games end (almost always) before large numbers of heavy artillery can be build.
Problem 2
Larger numbers of railguns (more than 2 or 3) are extremely ineffective, because they tend to waste all shots on the same target.
Solution
Introduce a second firing mode ("delayed fire"), which delays the blast just as long as the projectile normally (on maximum range) travels- similar to the chinese mortar-guys.
This would allow the player to set some of his railguns on "delayed fire"- they would then wait till the first target is destroyed by the "normal" railguns, and destroy another one (2 * <delay> later). You could additionally signal the current firing mode (-> tomahawks in ROTR), and/or give the delayed fire a small boost (e.g. +10% damage).
Yea, I know that suggestions are closed... but I felt that this are some really useful things, especially since they seem quite feasible (though I dont really know how much time/effort this would require).
--edit: typos