Less weapons?

It depends on the race that you play. Some tech trees have certain weapon groups, other tech trees have other weapons groups.

I believe, for instance, that the Korath have disruptors in their tec trees.

Other races get a new set of first generation weapons. Seeker missiles replace stingers for some races, which are very tiny missile weapons with a correspondingly high cost. Kinetic streams and scatterguns are cheaper yet bigger than lasers and railguns, respectively.

i've been playing as terrans; i guess they don't get any additional racial weapons. it does seem like there is less weapon tech to research now overall (at least for the terrans)

If you look at the Terran tech tree, you will see that they have solid lines in both mass drivers and missiles.

Beam isn't bad, but for the Terrans it is not nearly as good as for the Torians, Drengin or Korath. Easy access to Disruptors makes beam great for these races (as well as the access to the evil beam weapon tech). When I play Terran, I stay neutral so I find that the seven techs in Phasors make beam research a dead end compared to the other weapon lines.

With Terrans, I like missiles early (up to stinger or harpoon) for small hulls, and once I move to medium hulls, I transition over to lots of mass drivers. With Terran, you are best served by going for big hulls and special fleet boosting command ships. So you want a weapon class that will allow you to pack alot of units onto those big hulls. Mass drivers have the best cost:damage ratio in the game and are actually hull space efficient once you get up the tech line a ways. So you can afford alot of good weapons and fit them onto your ships relatively easy. Also they are defended by armor, which in my opinion is the worst of the defense tech lines (costly and not space efficient early).

As for Missiles, they are great early (fast access to a 2 damage weapon) and not too costly to place one on each small fighter (about as cost effective as two lasers or two railguns). But once you get above a certain point, the missile lines don't seem to improve as quickly per upgrade as the other weapons. Also each missile tech takes much longer to research, so they are slower to advance to the ultimate tech levels. Finally, missile launchers are generally used in slightly smaller quantities on ships of varying sizes when compared to md or beam weapons, so starbase ship assist techs are not as missile friendly.