I'll concede that grenades are spammy, but rockets aren't? I've yet to see a match with even one rocket on each side that didn't end with nothing beyond a few broken walls left standing. I don't see rockets being used to clear paths and lines of fire, I see them being spammed at every standing structure on the map in the futile hope that someone will get tagged. Futile against me, at least, because I never position anyone less than the diameter of a rocket explosion away from any sort of cover if I can at all help it, because I know for a fact that half of the walls on the map will have been exploded by the time the first shots are exchanged. At that point, it just becomes a matter of who guessed which directions to have their machinegunners aim at the best.
Maybe if rockets were limited ammo they would actually be used tactically, or if they were replaced by, say, C4 charges, but as it is they're spammed just as much as grenades, and worse, don't stop with pasting anyone inside a room; they also wreck the room. Now multiply that by every rocket fired and within a few turns you're (depending on the map layout) down to either almost nothing or a few intact rooms at the corners away from the spawns. Gog help you if you've got random spawns, because then first-round rockets will kill half the units before anyone gets a chance to go for positioning.
Also, what about the issue I mentioned with games ending in unwinnable rocket v rocket duels? That can't happen with grenades, because they don't need to hit a wall or light cover to detonate. Also, grenades are somewhat less spammable for the simple reason that they have limited range; rockets are LOS firing: If you can see it, you can blow the shit out of it. If you can't see it, blow shit up until you can. Practical, but inelegant, and IMO not in keeping with actual tactics, if you don't count "Explode everything that isn't you" as a tactic. To be perfectly honest, I view explosive-heavy matches (rockets or grenades)more as joke rounds that let me dick around and bum-rush people. I can see a single grenade launcher having a viable place on a larger team of 4+ units; it fills a similar area-denial role as the sniper, exchanging range and accuracy for AOE damage, while even a single rocket launcher per team makes the match into a round of "Everybody huddle together in a wide open space hoping that we'll get the first hit on the enemies with actual rifles", while my rocket guy goes around blasting out lines of fire to wherever I think they're hiding at. As in, clearing corridors of open space through thickly packed rooms that stretch across the map by applying explosives repeatedly. Tactical?
Again, just my opinion.