Well, I could and I used to. But that would make everything bigger, heavier and less cost efficient, of course. And that's something I, personally just cannot enjoy with my spaceships/Drones/missiles, I usually don't even use a stock limits.txt file because it, well, limits me too much.
Also, i don't like drones with single weapons anymore, because of the way target contribution stops working for groups of drones with one gun each.
But 3-5twr and 6km/s sounds impressive without future materials.

Using Future material pack is quite overpowered considering the available armour materials.
Can you build drones without it? To me, I can control the drone to 70t class which equiped with 60mw reactor, 1 main cannon, have 3-5twr and 6km/s dv.