The fire rate on the Rogue's cannons are much lower than the ones on the Lazer/Hydra/Savage. So, you can't simply pull the nose across a target while firing and have a good chance of hitting it.
When you combine the guns being in the wings and not the nose with the short range of all vehicle weapons in GTA, you have to worry about convergence usually spacing the rounds apart. A Hydra has both guns in the nose, so they effectively cover almost the same area, and the Savage has only one gun. A Lazer has both guns farther apart, but close enough together that the pilot can basically aim as though they are firing only one gun, but with the added benefit of covering more area with explosions when attacking ground targets.
The end result of the above being that you can't consistently place shots in the same spot, and that you can't hose the area ahead of a target and let them fly/drive into it compared with being in a Hydra/Lazer. I wouldn't mind either factor on its own, I don't even mind not having the easy mode of a Hydra/Lazer, but together these two factors just make for a frustrating experience.
Another note is that with the lower fire rate, the physics effects of hitting a target a way lower. For example, whereas in a Hydra/Lazer/Savage you can hose down one of the armored Headhunter vehicles and send it flying around with a hail of localized explosions, if you can even hit it in a Rogue it will barely be affected.