But I'd like to see a major exploration overhaul for S5. Done right, I think exploration would be our endgame and could solve a lot of the issues with the game while working in everything we're missing.
For example, one thing:
I'd make it so that exploration has persistent, procedurally made sector blocks and you use shipboard navigation to move between these blocks. Suddenly you've gotten away from the "ship in a box" feeling and also created a place in the game where shipboard navigation fits, where you're in "unknown" space between the sector blocks you discover..
I don't know if you've read the latest Engineering Report, but season 4 is clearly being developed.
Yes, Season 4 is 'in developement'. But, as the Nagus pointed out, Season 3 just started. Season 4 won't be 'underway' until it launches next year.
Season 3 isn't just what went to the live server 3 days ago, it is everything that will hit the live server between now, and season 4's launch. So, Season 3 is underway, Season 4 is 'in the wings' so to speak.