You're right that jump times are independent of jump distance, that's because it's a loading screen, it takes that long to load in the data for the new system. If they were to introduce longer times for longer jumps, the short jumps would still take the current (minimum required) time, so all it would do is introduce more waiting in a game already full of time-sinks.
If there were a 'creative mode' way to zoom into a system on the galmap it would somewhat undermine the point of travelling to many systems in your ship. You would already know what was there, so you would only visit those systems & miss the opportunity to be surprised or challenged.
I am currently doing the grand tour (anti-clockwise) in a fully equipped Corvette with a 19Ly jump range. With that low a jump range the galaxy is no longer just a connected series of dots, it's a maze with dead ends & clumps that can trap you without good planning.
I would not want that challenge to be taken away. Have you tried Space Engine?