Any discussion of P1 vs P2 on simplicity is really missing the whole point of this. How you design your reactor system to be optimal isn't what keeps players around or pushes them out, what matters is that you place some limitations that give tradeoffs so there isn't only one optimal approach and encourage ship variety.
The fundamental problem with StarMade is that there is a dearth of structure in shipbuilding and necessary support infrastructure in everything as a whole.
The shipbuilding problem is simple: The entire game is based around making whatever shell you want and shoving blocks in. This gives enormous RP freedom, but in the end it results in the most ideal ships for actually using being...no shell at all, just a twig with weapons attached. P2 actually is a big step to making this better (altho IMO it really missed what the core issue was), but fundamentally we're still in the situation where you just cram in everything else instead of actually trying to build something that makes sense with modules and hallways and whatnot.
Crew will probably help on this matter, but I think thrusters need to change too because right now they're basically just filler to add.
To further this, I think P2 would've been better if, instead of stabilizers, you simply would get some kind of extra damage from shots landing near the reactor, based on its size, so that an overly-huge reactor for its shell meant high risk and reward, forming tradeoffs. Stabilizers really don't do this.
As for infrastructure, the fact of the matter is you need nothing to keep a ship running, you just need a homebase to refine materials after making mining runs. This is boring. At the very least, ships should consume some resource like fuel to stay powered and fly about, encouraging you to expand your infrastructure as you get a bigger and bigger vessel, and making things less of a rush to get the titan that'll own everyone you meet. Without a resource requirement, things will always just degenerate to massive ships and camping on nothing.
Also, good infrastructure stuff means places to go. Right now, planets are just big asteroids, basically, instead of something you want to really interact with. Consider Minecraft villages and the crucial roles they play, or Nether Fortresses. Those are the things that make Minecraft good in the end, not the Ender Dragon or whatever achievement there is to earn.
StarMade tried a bit with pirate bases and factions, but it's all just empty structure right now. There's no real paint to raiding a pirate base, and you don't get good treasure. The factions are little more than annoyances as well. StarMade needs to really start putting stuff behind factions for the player to got to through them.