I don't know, honestly, I have a hard time seeing how something that lets you travel literally across the Sector, instantly and almost for free, could end up being useless.
I think maybe what you're feeling is that you won't be able to stuff all of the new things into One Perfect System? Which, absolutely true. But the game has been moving away from incentivizing colonizing just one system, so you might consider this one small step in that direction, too.
But even colonizing one system, there are so many options. You might have 3 stable points and a gate and use a wormhole instead of a sensor array. You might have two stable points and a gate, and have a colony at a gas giant, so you can sacrifice a nav buoy since there's much less in-system travel time. You might not have a gate in-system and use a wormhole to travel to a system with a gate. You might have a gate, and place a wormhole in a nearby system *with* a gate; a two-step operation to get across the Sector to a specific destination seems worthwhile. And those are just the scenarios that come to mind immediately.
The question there is, how often do you really need to jump across the Sector? And cost isn't really an issue since Gate travel already minimizes fuel consumption, even moreso if you have Containment Procedures. The thought had occurred to me that you might just link one colony system to a Gate system for convenience, but you're making the assumption that you have at least one Stable Location to spare. In my experience, most systems have either one or no Stable Locations, those with two or three are rarer and tend to be completely empty. Which means, unless you were touched by RNG, you need bare minimum one for a Comm Relay in your colony's system, and then you'd have to eat the 5 story point cost to generate another for one end of the wormhole. Is there a change coming to Stable Location generation?
You also listed using sensor arrays and nav buoys. Nav buoys aren't needed for (most) systems, and sensor arrays can provide their slipstream detection bonus from up to 5 ly away, so you don't need those in-system either. I don't think anyone expects to have all the toys in their system, and most people would happily sacrifice one or the other for a wormhole - if they had them.
One important thing though, but can you realistically expect to acquire a Wormhole Scanner and both Wormhole Anchors before getting the Janus Device? I'm not asking for spoilers, but if I can get and use both before I complete the current extant of the storyline (at a reasonable pace), it could affect how useful they are, even if it means I end up picking them up and moving them later.