There is so much potential gameplay benefits in unlocking a new more interactive mode of interstellar travel that it would be a crying shame if it never gets implemented. What we have just now is effectively analoguous to star treks warp drive for moving around systems in supercruise and akin to star wars hyper jump for moving between systems, what the OP is proposing is something akin to andromeda's slipstream method of travel and IMHO that could knit nicely with the current game.
Gameplay wise, it would be more interactive having to spend 30 minutes of flying dodging rapidly approaching stars following an onscreen vector indication (like interdiction minigame), rather than: [jump via loading screen, stare at witchspace animation for thirty seconds, blue tunnel into system, supercruise around star, blue tunnel into witchspace, rinse and repeat 30 times]
Furthermore, there could be a tie in with the design decision forum concept of hyperjump beacons that cosmicspacehead refers to, where we could only "hypercruise" into systems with a nav beacon, but players could witchspace into the unexplored systems, scan the system, and deploy a nav beacon loaded with all its cartographic data enabling future visitors to hypercruise to it. I think this could be used to create a new wave of exploration of our galaxy and could be tied into the exploration buff coming in the q4 update.
Hypercruise cannot be all milk and honey though, so there'd need to be penalties, I'd suggest if we used somethign like the interdiction minigame screen to control the heading, and had star sytems hurling towards the player, "deviation from the vector" ie losing the hypercruise minigame would pick up ship heat, and would destabilise the "hypercruise conduit" as indicated by the right hand progress bar moving upwards; if the right hand bar tops out the player would do an emergency stop with lots of heat plus hull and module damage, in essence they fluffed their hypercruise into a misjump. But if they were good at it, and kept on the vector indicated their left hand progress bar would climb, and they would be making progress faster than repeated witchspace/supercruise movements. So starting off they would be travelling at the same sort of pace in hypercruise as via witchspace jumps, roughly one kylie an hour, as they kept their ship on vector and their left hand progress bar went up that speed would increase, say maxing out at for a hypothetical value 5 kylies an hour. However if they fluff it they would lose speed and when they end up with only the bottom notch on their progress bar they would be travelling slower than witchspacing at say 0.1 kylies per hour.
Using those values above it would bring hypercruise potential speeds and therefore hypercruise journey times roughly in line with neutron highwaying, thus colonia which has been done in a matter of hours but only if the pilot is good based on colonia at twenty two kylies and five kylies per hour top speed giving it four and a bit hours theoretical minimum journey time...
https://www.reddit.com/r/EliteDangerous/comments/5l16tt/whats_your_speed_record_from_the_bubble_to/
Lore wise, we could twist it into the game that we borrowed / acquired technologies that enabled us to go from witchspace hyper jumps to hyper cruising long distances from the guardians or thargoids during the future narrative unfolding regarding the other two civilisations we know of in the galaxy.