The routing you did on the right-hand side is what should be done for all the groups, especially the airplanes. The AI is not to be trusted to "shoot from the hip" with tight routing. When we were re-doing Pearl Harbor a few releases ago, just about everything in the area had either a triangle or a tight box routing. A lot of the airplanes would crash, either into Ford Island, themselves, the hillsides, or the water. The ships would back into each other, or drive themselves into a corner and just sit there. If you watched for less than 10 minutes, you'd probably see at least 3 implausible things going on, all around the docks on the East side of Ford Island. Another thing is the spacing between vessels in the groups, such as Convoy 12 that you have there. Notice that there isn't any "definition" of a group spacing, since they built it by hand. How close together are they?
As a reference, we'll have to find you Rockin Robbins Convoy from H-E-double-hockey-sticks file. The "passenger" ships react differently from the tankers, which are different from the warships, etc. You can use that "Play" feature in the Mission Editor until you're blue in the face, trying to check your groups, and it still won't tell you how the groups will proceed in-game. You have to run the mission in the game and actually watch them in order to see it. If you look at a particular Stock SM xx file (cannot remember the name), they've got a convoy routed across dry land, and it drives several DD across that dry land in the ME's "Player" thingie. Looks fine from a distance, until you zoom in and see it do that. In the game, when the convoy gets to that particular area, all sorts of "collision avoidance" stuff kicks in, and the convoy, as you so aptly described, mills about like a bunch of drunken sailors that don't know how to read a compass, much less a chart.
Everything bunches up just off the shore of that island that isn't an impediment in the ME, and when I actually played the mission a little further than normal and followed the convoy to that area, I was able to sit off the island in the deep water, and pick the ships off at my leisure, king of like harbor raiding in Stock, having to move just a bit a couple of times while a DD came over to investigate, and then they'd get further confused about what the convoy was doing. Usually in that mis, I'd attack within 20-30 minutes, getting maybe two or three merchants before being depth charged for an hour and a half, and then losing the rest of the convoy (or so I thought)...
For me, this is the kind of stuff that makes a game "believable", if you get rid of the strange routes and downright strange make-ups of some of the convoys (how many BB and DD did the Japanese have again??), you not only make the "game-play" look better, but the game isn't "thrashing" as much and wasting cpu cycles on basically "drunken sailors". Keep up the excellent work! Now you've only got 90 more files to go through in the Campaign...
btw, will we be able to "borrow" your work when you're finished (maybe Rockin R already asked you... ??) for FotRSU as an optional Add-On?