*nods*
Personally, I think the mistake everyone made when you guys were retconning ship speeds and FTL tech and stuff was that you limited only max speed; what I think you should have done was also limit the max accel/decel for a given tech-level, ie 10 Gravities or something for new low tech races, 100 gravities for mid-level tech and 1,000 gravities for advanced tech races. Currently ships can accelerate at several hundred thousand gravities and stop on a dime with no enforced limit based on tech level... but with hyperdrive fold there is no real need to travel at high fractional lightspeed velocities like .4c anyway. Under most circumstances you wouldn't need to more more than a few thousand km/h to leave a planet, dodge weapons fire or to fight space battles. High velocity travel STL travel should be available if needed, but its use should be limited by large accel/decel times with long-range travel usually being accomplished by FTL travel.
Also, more realistically the max speed shouldn't be limited by the armor mounted by ships (at least not how it is currently; with heavier armor making ships slower. If anything, heavier armor should make your ships be able to have a higher max speed but accelerate slower because of increased mass. Because the heavier armor is protecting against impacts from interstellar particles hitting your ship at high velocity it should theoretically allow you to travel faster more safely by protecting hardware and people from radiation). Though another method of limiting max speed would be based on the strength of a ships shields; the stronger the shields, the more they can deflect particles at high speed and the faster the ship could go (ie it could be based on base shield strength, with 50 SP ships able to travel at .5c and 25 SP ships able to travel at a max of .25c, or it could be based on the shield threshold instead or some arbitrary limit based on tech level or something).
I can't really think of much technological reason why a ship shouldn't be able to keep accelerating past .4c if their engines are still working, beyond particle radiation due to high-speed travel within a solar system. Although for RP reasons making .5c or .6c the limit that shields can protect people from particle radiation would probably be a good idea for manned ships (missiles and probes probably should be permitted higher accel and should keep a .9c+ limit so they can actually outrun stuff in combat) -- after about .5c, you start getting noticable time dilation which would make things wierd to roleplay.
Even the smaller FTL limits of earth-like planets would take longer to travel and have some more impact if we didn't have the current utterly ridiculous accel/decel for our spaceships; I can accept that ships have some kind of exotic mass-cancelling fields or something that makes such acceleration possible but it makes the battles around planets utterly insane. There is utterly no way for flesh-and-blood fighter pilots to properly navigate and dog fight each other when travelling around at .4c and you'd never be able to eyeball your targets; every race would either have to have some sort of high-speed brain interface like SPINE and only control their fighters by that means during combat, or else fighters would have to be computer controlled. If acceleration and beam-weapon ranges were more limited, we could have battles closer in and more like how they are depicted in SF shows and movies, rather than at ungodly long ranges of hundreds of thousands of kilometers in order to allow enough reaction time for people to actually do something. As is, in battles around a habitable planet it would only take a couple seconds for a ship to reach the hyper-limit and run away if they wanted.
Also if we han limits on accel, then afterburner tech and the like could be brought back in some form; use of afterburners would increase acceleration and allow ships to reach their max speed faster at the cost of fuel/power, but not increase the ships max speed.
...okay enough random ranting. Feel free to ignore me