Roadmap

At least one new equipment piece for each of the 3 current player ships - one will decrease the delay on the Relief's healing ability. This will also see the first equipment pieces with more than one ability (and all abilities might not always be positive ones!).
Choose what level to start the free play mission (from 10% to 90% of maximum level reached).
Mission difficulty (Hard and Insane). This will bring bigger XP gains, more upgrade points and guarantee drops on the first run.
Equipment boxes for player ships obtained with XP. They will provide another way to get levels for existing equipment, either for all ships and a specific ship (there will be options for both, with different costs).

3 new player ships. At least on DPS and one Support, third one not guaranteed to be a Tank. Might be another Support. Still undecided.
New ships will have different amounts of equipment slots.
Volume 2 missions. Variable number of ship slots on different missions. Maybe the return of a solo ship mission?
New equipments for the new ships as well as at least 1 new piece for each of the existing ships.
Missions to award levels to specific equipment (and unlock it if you don't have it yet).
New bonuses and achievements.

Re-spec upgrade points (with an ever increasing XP cost).
Player ships alternative paint jobs.
Rework of the bosses, with different attack mechanics, defense modes (shields maybe?), names, and modified visuals over the standard enemies.
Static targets.
Volume 3 missions.
New bonuses and achievements.

Ship pilots. They will have their own skills and levelling up. XP will be earned if they are active in a mission, and will automatically unlock their upgrades once they reach the required level.
Pilot's skills will also be upgradeable with the XP they have earned. This will be separate from the global XP used to upgrade ships and acquire equipment boxes.
New achievements

First look at active gameplay, where the player controls one of the ships.
Planet building. After all these attacks, researching the planet's infrastructure might provide a nice bonus to the ships and pilots fighting capabilities.