Ideally a drone would be a very small craft. Vague estimations based off nothing at all put the size at maybe 5x8? Not counting engine overflow, because they have thrust squares that cannot be built on but can be passed through. The barebones speed fighter would likely have no hull at all, just bare components and a lot of thrust. It would rely entirely on speed and crazy maneuvers to survive, to which I can see two types.
The first would be a swoop fighter, made sleek and agile and able to use its momentum as an aiming tool to line up shots and careen towards an enemy and then skim past them. This design would require very high energy demands and significant engine power to keep its mobility high enough to evade fire. The advantage of this design is being able to harass the enemy and confuse the enemy gunner, as well as getting into a good firing position where it can knock out engines or get into a blindspot. It can additionally move troops very fast, anyone who foot-locks onto it would be able to ride it during a swoop and jump over to the enemy ship and begin boarding. It could also be mounted with an extra turret for more firepower, but that would get tricky. The disadvantage is the fragility of exposed components and the low durability of lightweight hull materials, and the expense of mounting good enough engines to keep it alive. It also requires a skilled pilot.
The second, more likely design would be a sort of armed satellite. It would mainly have strong maneuvering thrusters in the 4 translation directions, and only need weak rotation and drive engines, along with a strong gun platform. This design would sit at range and use powerful strafing engines to dodge incoming fire while its spinal mounted main gun could take pot shots at the enemy. The advantage is having an artillery weapon platform that can mount any large gun and evade fire by keeping itself at a safe range where it can dodge incoming shots but the enemy ship is too slow to dodge. The disadvantage is that it would have slow turning and low drive. If it ever got flanked it would be pretty much defenseless. However, it can mount additional turrets relatively easily for extra pilots to control the guns while the pilot tries to evade fire, and the pilot doesn't need as much skill to strafe and evade as you would for a swooping ship.
Of course for both of these designs you have addons. Both can use more armor, the armed satellite could use rear turrets to take down intercepting fighters, the fighter could do with more hull and more turrets... but as you make the ship bigger you lose track of the goal. You're not trying to make an indestructible ship. You're just trying to make a ship cheaper, so that if your ship and the enemy ship both kill each other, your ship is cheaper to replace. You might lose two satellites facing an enemy cruiser, but if your satellites cost you a few hydrogen and some guns, and the cruiser was packing antimatter and nuclear reactors, then your cost/kill ratio is way better.
I'm personally extremely curious to see how big ships will evolve though. If you mount all your guns on one side, you've got the broadside advantage and can shoot down any single ship. However if the enemy deploys a fighter and flanks your undefended backside, then you're getting hit on your soft spot and that's not going to help. If you spread your weapons across all your surfaces, then you become more versatile but less powerful. Add in drone satellites, other unmanned vehicles, boarding attempts, and all other sorts of cost/size complications, and I really have no idea how ships will end up looking. And this excites me. It's going to be very fun watching the Bay12 combat rings and seeing how designs play off each other and try to find middle grounds.
Also gonna be fun when we take it to other servers. Game like this won't go long without tournament play, and you KNOW that Bay12's gonna have to develop an arsenal of tricks and ploys combined with pure firepower to deal with any outside enemies. The first widescale fights are gonna be epic.