This is all absolutely brilliant. You've taken Traveller's most stale skill and the most meh aspect of Traveller space travel and developed a system full of excitement and role playing opportunities! Jumpspace weather and jumpsace rutters draw on Traveller's Age of Sail roots in cool ways. You are a genius!
I am not sure if "rutters only working when nothing changes" is true. Rutters worked because they contained rough knowledge of currents and positions and no one knew much of anything in the 16c. Old school rutters were sometimes accurate, sometimes not. But something was better than nothing. Case in point, those sketchy 16c maps of Southeast Asia.
Jumpspace rutters would work because they offer some imperfect (but usable) understanding of jump currents and jump weather, not because they track the realspace cosmos in all its glory.
Your ideas are an exciting variant for Traveller! How can I learn more of your exciting ideas? Cheers, mate!