The explorer role looks like the best one so far! I am very excited for the things you plan to add because those are what ive always wanted in this game. I hope no one starts complaining about certain blocks being locked behind dungeons because boohoo that ruins their precious "get 100% of the content from the start" sandbox game. Idk if its possible in SM but kind of like how Space Engineers has turrets and guns that aren't made out of blocks, but are stationary tools-that I would love to see. It'll make small ships more fun that way. Idk about the rest of the player base but I don't want EVERYTHING to be blocks.
As for the warp gates thing...to be honest they arent very useful. You can only use them to go between A and B, but if you want to go visit your friend at C or a far away shop at D, you have to make your gate, fly away to the new location and make another, and then go back ALL the way because you forgot to connect and then fly back again! Jump drives are wayyyy to slow unless you want to sacrifice 40% of your ship for them. Chain drives are fun, don't require you to hold down the mouse button forever, and much more fun than pressing W for 20 minutes at a time. You should just introduce official chain drives, and find ways to nerf them like after using your shields stay down for 5 minutes, or you can jam for 10 minutes, weapons deactivate because of "over heating." But a long time ago you were going to add hyperdrive which I still want to see. that's how it is in all the scifi games like Halo. I think you should reconsider that idea. Make it so you can only fly straight ahead, but you go incredibly fast, and it takes time to slow down too. And you cant exit hyperdrive in the vicinity of a station or planet....or you can but there's a threat of crashing into it and destroying your ship. Wheres a lot of things you could to, and they would all be better than teleporting with jump drives. With hyper drives you could make the number of modules determine how long you can stay in that mode.
One other thing id like to see with the universe updates are skyboxes that encompass larger areas. Right now each system has its own skybox which makes space feel really tiny instead of really big because you can fly in any direction for 5 minutes and it looks completely different, but your speed doesn't relate to that at all. Lastly and most importantly, I would rather have 40 huge planets in and around the galaxy rather than 500 small ones. This is a controversial opinion but quality over quantity right? Real planets with more than 30 block dirt depth and Id rather them be huge cubes because usable surface area is much more important than how they look like from far away! Maybe make them indestructible too if that lessens server load, because what is the actual point of destroying planets other than making mining lag free lol.
Someone else on here once mentioned instanced planets and that is still the best idea in my opinion. As long as you make it so you can still fly smallish ships in the atmosphere/leave them floating up there, It wont break immersion for me at all. I don't quit playing Minecraft because I have to wait for the Nether to load.