@MissSnowiieYou're right, the speeder bikes are a waste of battle points. At least the Clone Wars era ones, but I didn't really get to play the others. They received a nerf because they were once way too powerful against everyone, but let me explain:
They have been nerfed to the ground so that the barrage ability (the main gun too?) only does laughable damage now and, more importantly, they completely screwed up the aiming behaviour as you have experienced already, which doesn't help to deal with the damage nerf too.
Before the nerf, the speeder HUD was wobbling around like crazy, but at least you could land your shots properly. It also appeared like they had some homing effect.
Now the HUD is stable, so the crosshair no longer wobbles around, but at the same time it's near impossible to aim anywhere else than the center.
Try to aim at a soldier near you, it's almost an impossible task without maybe switching your mouse dps up in that moment. That really wasn't a problem before the nerf, even as it looked really weird. Also, your aim has to be absolutely on point now if you want to get anything done.
Just use the Droideka or Republic battle walker for getting from A to B fast, killing camping snipers and destroying tanks. The speeder bike won't get this job done anymore.
TL;DR: The speeder bikes went from godly overpowered to completely useless. Good job EA.
No one uses these anymore; I still haven't been encountering a tryhard yet who has mastered the CW era speeder despite the nerf. This fact alone says a lot imo.