Pretty straightforward idea here, if a little whacky at first.
What if the cost of travelling in Hyperspace was sidereal time in the non-Hyperspace universe? I.E., there'd be <some multiplier> on time when in Hyperspace; local time is as usual, but subjective time in Systems is passing faster while traveling through Hyperspace.
This would:
1. Encourage players to invest time finding Wormholes (which I'm still presuming will be a thing at some point).
2. Encourage players to get the Gates working again.
3. Allow Alex, from a Game Designer POV, to de-couple "what's happening in Hyperspace" with "what's happening in Systems" in a way that makes sense. This would help with the performance issues, because explicit manipulation of the traffic in Systems, etc., could be fully abstracted away; the player's fleet and primary POV is not just separated in distance, but in time. This could really help the game maintain good framerates as things scale up, planets get inhabited, etc., etc.
4. It'd give a very good excuse for Outpost populations to be able to rise in a reasonable (real-world) time rate; with Hyperspace travel eating months of subjective time in Systems, for example, there's a great in-game excuse for, say, populations to grow, giant space installations to complete building, etc., etc., while keeping the pace of these things reasonably slow if the player just stays in the System.
5. It'd also give a reasonable explanation of why Pirates can build their own Outposts pretty fast; they aren't, it's just that their locations are <insert weeks / months> of travel-time away.
6. It'd be a nice nod to Relativity in a semi-realistic sci-fi game.