Nerf the Titan and Flamer troops

Flames/Shock Troopers are strong in that they can melt infantry, but they do very little to vehicles and cannot attack air. A talon or venom will heavily tip the scales against someone who is spamming them, or a buggy/rhino will do as well. The game is about having the right answer to the situation, not brute forcing things that shouldn't work to do so. 

As for titans, there are multiple counters. As you said, rocket squads will do in a pinch, but if they have titans and all you can afford is a rocket squad, you are in for some trouble. Air units can deal with titans decently as well, but it will take some time. Zone Troopers/Cyborgs are the proper tech response to titans and can take them down with little difficulty. If you are having trouble with anything in particular, join the discord and chat us up, we would be glad to help. 

But nerfing flamer/shock troops and titans just to make things that don't normally counter them become counters is a poor move from a balance perspective =)