MMO in form of "buy once play forever" like with Guildwars, would be ok
but when it becomes pay to win aka free to play with item shop, motivation to invest any time
and paying a regular monthly fee ... no thank you.
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endless grinding games also would be just boring
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but

if you can somehow safe your empires after playing and get back into the game next time you got time, perhaps even chose a neighbouring starcluster of a friend where you continou playing(please no guild/clan system) and chat messages only if you have researched that stuff and the language of teh dude you want to contact or he you otherwise less communication is more relaxing.
race creation with good traits which cost points and bad traits which gain you some points?
heroes?
artifacts?
tech trees with race specific or race trait specific techs?
uniq drive tech like in SotS?
Diplomacy&espionage?
3D Galaxy view? jump points between galaxies ? 1 Galaxy 1 server?
Trade?
Mega Structures ... Stations are small, how about Orbitals and Dyson Spheres consuming astroid belts, Gas Giants, Baren planets in teh making of them?
"SIMPLE" research & ship design? wherby the research should give us tough choices so we need to pick and choose and also not everyone would be even aible to every option to pick from.
random events and news?
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well the stargazer teaser sadly crashed but i am looking forward for your a playable alpha or beta, let me know when you need a tester.