Remove star clusters. What??? Seriously, listen. The current star cluster missions are really just random "patrols". Your not discovering anything new, your just patrolling already known sectors and fighting bad guys or scanning anomalies. So until a "real" exploration revamp is done, how about removing the clusters and letting every planetary system be a doorway into a random mission like the star clusters.
They would work the same way as the clusters, with the sector block determining the types of NPCs you would encounter. At least that would be more visually appealing than flying around in circles inside an empty box.