Modal Mapping-
This is yet another of my constant bug-a-boos.
I would listen to a few of the many, many versions out there of either "So What" or "Impressions"...if possible, transcribe what the bassists(i.e. Paul Chambers, Ron Carter, Jimmy Garrison, etc) are doing.
If you do find the bass "hidden"(& I can relate)...check out the Aebersold book/cd that has "So What" & solo the bass track!
What
may help, too is this-
Vary "the feel" somewhere along the path.
In lieu of constant swung 1/4 notes throughout, maybe try a Latin-ish rhythm (using 1-5-8? Add extensions/chromatics as felt) over a chorus.
This does a couple things:
1)Helps break up things
2)Gives you some time to think of the next few walking bars
Another device to try-
Pedal over a few bars(staying on ONE note).
...also gives you a break!