I think that there are 3 general balance problems involving engines:
1) fast ships are on the strong side compared to slow ships
2) engine rooms are basically mandatory
3) big thrusters are more useful than small thrusters
Obviously these are all somewhat related (especially 2 and 3). But since fast ships vs slow ships (#1) is going to change really heavily with the introduction of the new missiles, I don't think it's a good idea to globally nerf thrust. If engine rooms need nerfs (which I think they do), then it's probably necessary to buff thrust in other ways.
Walt From a thematic standpoint, it may make the most sense to remove the ramp-up time buff, since engine rooms are primarily used on larger ships and larger ships should generally be less maneuverable than smaller ships.
I'm in favor of this, though big thrusters might need a ramp-up time decrease to partially compensate (say, -25% ramp time?)
Also, I suggest buffing the small and standard thrusters. Would it be reasonable to remove ramp-up entirely from the standard thruster, and give the small/maneuvering thrusters reverse ramp-up? (so that it starts at ~200% power and drops to 100% power over a couple of seconds.) I think that reverse ramp-up fits thematically with the idea of a thruster for short bursts of maneuvering, and small thrusters could definitely use the buff.
If small/standard thruster grids become a problem, I think it would make sense to increase small/standard thrust exclusion zones. That way small ships (which have plenty of surface area and don't need grids) would do great with small thrusters, and large ships (with their constrained surface area and volume) would be better off with bigger thrusters. IMO it makes sense for big ships to be best with big thrusters and small ships to be best with small thrusters.
Hopefully, the net effect of these changes is that smaller thrusters would be viable on their own (allowing small ships to be reasonably fast), and engine rooms would no longer be a must-have on large ships (still cost-effective, but more of a tradeoff)
Of course, I did just say at the beginning of this that a lot is changing in 0.14.5, so maybe it's not a good idea to add even more changes to the mix? I'm not sure what makes the most sense.
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And a random thought: would it make sense to change thruster names down 1 level? The small thruster would become the maneuvering thruster, the standard would become the small, and so on. Not particularly important, but I think the name "maneuvering" fits well with the reverse ramp-up idea, and if there was ever going to be a bigger thruster there's not a lot of room above "huge" for a new name.
Finally a random question: Do engine rooms make thrusters ramp-down faster too? Or only ramp-up faster?
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Equalizer Maybe the engine room could be made explosive like a reactor.
I'm not against this, though I don't think it would have huge balance implications (unless they were ridiculously explosive). It does sound cool and pretty realistic.
samepage As I mentioned, this is more than simply about balance. Without some change to correct this, sooner or later this building style will become the only option to build in competitive multiplayer. Just observe the recent and following up tournaments and you will understand my concern.
Yeah, but the style on the left has never been viable in competitive multiplayer. I personally think that the current engine room clusters are a big improvement (aesthetically) over the previously style of distributed internal thrust and big flat thruster walls.