Modular everything: an overhaul and update to engines, weapons, storage, etc.

what is something that would vastly improve Space engineers, a game about space engineering?

In terms of preserving old SE history, i propose we have two kinds of part: the prebuilts we're all familiar with, I.E refineries, atmos thrusters, large hydrogen tanks, etc. "whole" modules per se. these'll be used by the PCU-minded, and those looking for a more arcade-y experience, like a significantly better version of minecraft. this requires no changes to existing things besides a bit of relabelling of files for interactions, maybe. idk I'm not a coder

Then, the second part: Modular components

these'll be for people who'd prefer a custom turret over a default one, because: superior firepower>durability in most cases.

for things like engines, you have the basic 3 types of Ion, hydrogen and atmos, but they come in about 3 parts: input, which handles whether it uses fuel or electricity, or even both, and then there's the main body. this dictates things like fuel efficiency, base thrust and environmental use cases. the last part is the output: this can be a nacelle for turbine-like engines, or a nozzle, like traditional ion/hydrogen engines, and further boost/re-spec existing engine statistics. (for things like electric engines, just having the input is enough for that engine to be considered electric)

the inputs and the outputs can be mixed and matched (within reason) like a hydrogen fuelled jet engine that gives amazing thrust, arguably some of the best in the game, further improved by using a rocket nozzle as an afterburner module, but suffers limited use because it can only work in, at the worst, Pertam atmosphere and requires hydrogen, which needs additional weight. Engine bodies designed for heavy lift could be "Gas-guzzlers" so to speak: sucking high amounts of hydrogen in exchange for extreme heavy lifting. this forces the engineer to compromise with thrust: weight on larger crafts. For use w/autonomous blocks, the body controls whether the engine's on/off/thrust overriden

On something like Weapons, the answer is much simpler: if the weapon is divided in a similar way of loader, reciever and barrel, it falls in a similar pattern of input, body, output. this wouldn't require nearly as much finicking but allows for even greater customisation and combat specialisation. for turret reading, and Just like the ATF, the reciever is what's used to register as a weapon.

Lastly, for things like storage, while it is already pretty modular, there is further room for improvement. this is more of a semi-functional reskin than anything, but things like O2 tanks and hydrogen thanks that are reskinned such that it's more like stacking cylinders and capping them with two round tops, as seen below, but could also work for things like storage containers, that while functionally are all different blocks, appear as one big unit. this one is more for aesthetics than anything (though you could do a funny and use it to make explosions that have a guaranteed chain that's even larger than standard H2 tank blast-chains)

then there's a few misc things like

• rover engines that boost the power of the wheels
  
• more specialised refineries/assemblers
  
• modular reactors/h2 engines
  
• more complex energy generation using a rotor modified for generating power from motion, rather than using power to generate motion.
  
• even larger tools using a rotor and a very large block like a drill bucket or an almost comically oversized set of saws, both ranging from 3x3-7x7 range of size for large grid/small-grid-gone-large
  

For all of the above, the more variety there is, the better. for this, I'd make about 3 sets of each, as a starting point, then ask the community for further ideas if you get stuck. you guys could even get creative with things like new fuel types using explosives/magnesium or having oxygen piped into hydrogen-powered engines for better efficiency/power at the cost of complexity. This whole thing was inspired by the recent modular turrets/solar panels and modular A.I, as well as the generally modular nature of production blocks of all kinds.