Yeah,
The more I think about it, I don't see auto avoidance working. However, I would love the ability to tell my ships to not choose to use a wormhole(or even better, the ability to add a high "weight" to the wormhole, so they would still use it if theres no other options, but it would look much worse when there are other reasonable options.
This would also be useful when I go around a IV planet at the start and have something like:
A - B(IV) - C
\ / \ /
D - E
At times, when the wormholes are close enough in B, you are forced to manually tell them to first to go D, then go to E, then go to C(since skipping any of these steps will make them choose to cut through B and die). If we could assign weights like:
6 6
A - B(IV) - C
\ /6 \6 /
D - E
Then, unless you told units specifically to go into B, they would avoid it, but when you gave them an order to go to B, they would take the shortest route(as all routes into B incur the extra 6 "cost"). I only suggest the edge weight over a node weight as it allows one to solve both this problem and the perma-mines problem.
However, even the ability to say, don't use this edge unless you have no other choice(aka to set edge weight to either 1 or something large enough, say 1k), would be enough for most of the problems, without turning the game into something where you have to mentally solve a weighted shortest path problem to figure out the optimal way to assign edge weights to get your ships to take the routes you want
.