You only get better acceleration (not delta-V, these ships don't seem to use propellant for in system travel) for forward thrust.
Delta-V is just physics shorthand for the change in velocity over time; doesn't matter what's causing it. Forward and backwards thrust is purely arbitrary and can be controlled by modders' numbers; strafe, on the other hand, is some magic number that we're not currently allowed to tweak. Anyhow, that's a side topic.
More or less: I don't get it. Could you demonstrate with a video or something?
It's pretty simple, really; ships with most of their DPS on side arcs need to act like ships do in sailing-ship sims, where they attempt to keep their side, not their front, facing the enemy. Look up "crossing the T" on Google and read a little about how naval warfare worked before the WWI / WWII Dreadnought-style of warship became the primary design.
That design, btw, can deliver both maximally-effective broadside fire and better firepower whilst in the chaser role, allowing the RL ships to kite by delivering a broadside while at flank speeds every time they were able to gain enough distance on the vessel they were pursuing.
For pure space warfare on a 2D playing field, neither design is actually all that efficient, because the rear guns will almost never get used due to the inefficiency of broadsides; the best firepower is always going to be a flying-wing or globe design, for either converging broadsides while kiting or a concentration that no amount of counter-battery is going to block; both designs offer strong advantages and disadvantages.
But I wanted to put some of this kind of design in and give them enough advantages that they'd be useful and provide something different to shoot at, and what I'm finding is that the AI just doesn't use them right, no matter how they're stacked. For example, if I put weapons onto the side gun positions that greatly outrange anything else in that turret category, giving it a definitive advantage, it still won't attempt to circle the target, even though at that point it's advantageous to do so, due to using its delta-V to force the opponent to burn delta-V inefficiently to continue to bring itself into range, while the whole period is increasing the accuracy of my fire. IOW, there are actually some situations where using broadsides makes sense even in a 2D game like this; same argument can be made that if all ranges are equal and the opponent cannot gain a range advantage and permanently kite, if a broadside provides greater DPS, it's time to circle.
But the AI isn't doing any of that; it's largely unaware that it's stacked for broadside behaviors and doesn't appear to take these things into account. So I saw my long, skinny warship that was stacked to kill a lot of minor vessels in a couple of volleys, if it used a broadside and forced the enemy to approach it on that arc fly straight at the enemy, and occasionally turn enough to deliver a partial volley (due to range; remember those front guns are quite a few pixels forward) which cost it delta-V and wasn't effective.