What you are explaining isn't grind. Rather scarcity and progression. Both very important for different reasons. When it comes to exploring, because places take so long to reach, it creates a sense of accomplishment. Something explorers are after. You don't hike to the top of a mountain because its easy. Don't jump hundreds of times. Visit the systems you jump to and explore them. If that doesn't sound appealing then exploring isn't the activity for you. No amount of jump range increases is going to change that. All it will do is devalue places people like to visit.
The work something takes to achieve can be part of what makes the achievement rewarding. I don't think anyone fundamentally disagrees with that, I certainly don't. The thing is, the work can be engaging. The games I consider well-designed make the work itself entertaining. Getting someplace in Elite is something I don't consider entertaining, fun on its own or even something that requires any skill, so I call 5kly for Palin a grind. It's not really about how long it takes.
In WoW for instance, the progression element is engaging and fun at all levels (and to be fair to Elite here, they have 13 years of experience in this). It's not just the fact that you're busy all the time (unlike scoop 'n' jump, point 'n' wait), it's that what keeps you busy is entertaining and engaging.
The optimal way to progress in any game, IMO, should also be one of the must fun ways to progress.