i was actually thinking about making a thread about this as well... >.>
i know this has been suggested many times before. i know the idea is that travel should become more interesting rather than faster and/or easier to skip, and i really do appreciate that mindset. the v0.7 features definitely added a lot towards that goal, with sensor mechanics and related abilities, terrain, expanded battles, and travel speed rebalance. travel often is interesting now, even quite challenging at times.
yet despite all these things, there are still frequently rather long travel times where nothing is happening and it's just about waiting with the shift key held down. i don't think that's really a problem by itself; some calmness between all the action can actually be rather nice, and it adds to the feeling of distance and emptiness of space. but if my finger starts hurting from pressing down the "speed up time" button too much, that's not a good sign.
as the others have mentioned, i think giving the option to make that button an on-off-toggle would already help a lot. and, personally, i'd also like to see the time sped up a little more. nothing crazy, but something like 300% instead of 200%. there will still be many times where speeding up time would be a bad idea, where controlling your fleet more precicely or being able to quickly react to enemy movement is important. but when the "speed up time" button is being used, i don't think making it a little faster would be detrimental.