Greetings, here's an idea on online gameplay i got. This would not have dedicated servers from Fractal Softworks so there won't be a subscription, but anyone could set up their own servers with their own mods and rules.
You can only have one ship (no fleets), but similarly to EVE Online you can buy and sell ships and equipment and fit/use them as you want, but you can only fly one at a time. When you login into a server most ships and equipment would be locked and you have to fly your starter ship and earn experience. Experience will act as Credits, you have X amout and you can spend it to purchase upgrades and skills.
You could start by having skills for Tech 1 blasters, lasers, machine guns, basic rockets and frigates. As you win the first battles you can unlock the first upgrades such as Tech2 pulse lasers, railguns, PD weapons and hull modifications. After that you could unlock another frigate hull or your first destroyer hull (Support or Carrier, etc...), giving you access to your first Medium sized weapon (that you unlocked before). You keep going like this up to the largest capital ships. Hull mods are based on each hull, so unlocking a Lasher frigate hull mod will only work for the Lasher frigates, if you get another hull you have to unlock the mods seperatly.
Obviously servers could configure this and simply set all unlocks to 1 EXP so any new player can just hop into any ship and start blowing things up. The idea is to have Free for All battles in a system where it's basicly the same thing as now but with several players. Any battles would occur in real time so if Players A and B are in a battle Player C can fly to their location and join the battle in real time.