The suggestion's rather simple. What I'd like to see is a sub-container, like the seed pouch, able to hold the bait used for fishing - leeches, worms and intestines.
When fishing with these kind of bait, it's a lot of hassle to micromanage the various containers in your boat to get the new bait after you've gotten fish. In addition, some fish also takes so much more space than the bait (eel etc), meaning if you stocked up full on bait, you have to dump it to fit the fish into your stash. The current system also limits the ammount of fish you can keep in your inventory before you have to drag out a container from your storage compartment, meaning there'll be so much time of annoying faffing about with container juggling and less time for relaxing fishing goodness. Storage of bait between fishing runs would also be easier, as instead of having three cupboards filled with random guts and leeches, I could now have them placed in tidy little sub-containers.
As for the container, what I'm envisioning is a glass-based cylindrical container - a glass jar. The name should probably be something else, to avoid confusion with the regular clay Jar, but the point is to make glass, and with that sand, more useful, as it's got very limited uses currently. I imagine 2 raw glass combined into 'unburnt glass jar' which should then be burnt in a kiln for 20 minutes to complete to make one of these little babies. Quality would be irrelevant - it would hold a base 3x3 space for bait.
It's skill dependancy would be Fishing. It's construction category would be Craft > Ceramics > Glass Jar, or Craft > Tools > Fishing > Glass Jar.
I suppose it also could mimic the seed pouch right click ability, meaning that if the fishing rod was placed in the inventory, one could pick up the Glass Jar with left click, then rightclick the fishing rod to have it baited instantly, instead of having to open the container, picking up the bait then rightclicking the fishing rod.
Anyhow, that's it. Thanks for reading.