Had a chance to play a bit last night for the first time in weeks and I think I'm getting close to the endgame. I managed to get a plasma or EMP armed Firestorm over every nation, shot down the overseer ship and now I'm getting ethereals an sectopods all over the place! My current plan is to hold off researching the next bit until I've made enough mind shields for everyone. I'm also on a recruitment and training drive, hiring soldiers by the dozen and sending them all to the psi labs, then dismissing the ones with no psi gift. My aim is to have enough psi able solders to make up two full squads.
No battleship mission yet though, which is a bit of a bugger since I gather you need that to upgrade the missile launcher. I really think they should have had a mid-level upgrade since standard rockets have limited utility. What would have been nice is a weapon that does higher damage with a smaller AOW so you can take on heavy enemies without damaging too much of a ship and with less of a friendly fire risk.