[Andrés]

That’s the point of having a complex tech tree. You can choose to research DUCs and have a good weapon early or research APBs and have a better weapon later.
If you want every new weapon better than the previous and worth using in a new design, you’d have to put all of them in the same technology and get one after the other.
And stop with that. You don’t have to compare damage per hit, compare damage ratios. A bigger weapon is a way to hide it’s worse. You’ll be forced to put less weapons in you ship and your firepower will be REDUCED. You still have to wait to get a smaller one.

There is a balance problem in research, some weapons are really hard to research but are not so good (IPM), and some are very good and too easy to get (PPB). Some others are well balanced and worth every research point you put on them (APB).

I made a XLS file to compare weapon usefulness with its cost. I’ll post it later.