If it's something they're planning to release this year then it must already be pretty close to being finished.I doubt Frontier even know themselves what it will be yet. It will be a tough decision for them to make having to balance it between being good enough for the lifetime pass owners and not too good to upset the rest of the players.
When you look at Frontier's other big game, Planet Coaster, it's clear they've already developed some pretty sophisticated base-building technology. Since they've already got it, they'd be mugs not to monetize it further by selling it to us. Design your own stations, megaships and planetary bases.
The galaxy can spare a system to hide your rubbish in, and anything half-decent and not bearing too much resemblance to a masculine appendage could even be included in the rest of the game. We build out the human content of the galaxy and pay Frontier for the privilege!