I have never said its good gameplay, but I see no reason to change it. Going to these far out places is purely optional and they are reasonably rare so it doesn't impact other players much if at all. I find the argument that it reduces the gameplay available to other players is a very poor excuse.
I am all up for faster supercruise or ways to introduce a more dangerous and costly way to get there faster via supercruise, but it shouldn't make the slow way obsolete, it should just be another option available.
Basically there is no reason why we cannot have long distance journeys and short distance ones like we have now. For people who do like to do them, there is no reason to deprive them of it.
I think that thinking about whether an activity is optional or not is misguided. I sounds to me like a sloppy cop-out way of dismissing critics to well... nearly anything in ED really.
The better question is : Is the activity on its own providing a good return in term of fun and challenge over the time invested in it.
For long distance SC the answer is : no. It's not providing a good fun/challenge for the time invested. In fact it stand slightly above : watching a screensaver or loading screen.
Which is bad. Gameplay that can be compared to a screensaver is really bottom of the barrel IMO.
Time vs Reward is a poor way to design and balance activities. Skill vs Reward is way Superior.
That is : to make long distance SC travel better, one need to make it skill consuming instead of time consuming.