Well, the thing to remember about the sustained beam is that while they are very, very powerful, they also leave your ship extremely vulnerable after each shot, with flux often very close to, or reaching max level. This means that ships like the Skaal are exceedingly vulnerable to swarm tactics, where while the ship can take out 1 (or 2, if you're lucky or a good shot), the rest will quickly tear you to shreds as you lack the flux to effectively use your shield. if you vent, your enemy might kill or cripple your now defenseless ship. if you don't, you have defend yourself with 2 PDs and no shields while your flux slowly decreases.
Mind you, this also applies to ships with shields that could tank your shots, such as the Tri-taychon Aurora or, to a much more lesser extent, the eagle. What do I mean? well, try going in game and attacking an aurora or eagle with a "standard" loadout. As it is in the current game, an AI controlled Skaal with the default loadout will find it very difficult (if not impossible) to kill a standard eagle. and, in turn, even a good player will find it very difficult to put down an aurora with just the standard loadout, as the current flux dissipation rate (both by venting and simply by waiting it out) are simply insufficient for the job. As such, I have to disagree with your assessment of the beam's OP-ness

. While its true that it is a very, very effective ship when used in the right hands (there is nothing more satisfying than watching a destroyer simply
melt when I shoot at it

) the nature of the ship is very much a high-risk, high reward kind of vessel, and I kinda feel that nerfing the damage without touching the flux will make it lose that very delicate balance of power vs vulnerability, especially if nerfed to 250.
...
...
then again, I may be kinda biased, primarily because watching destroyers melt like butter is very amusing to me
