This all sounds great, until you realize that what makes slow cooking so magically wonderful is that the heat and moisture of the cooking food is trapped to keep everything warm and cozy for a long time without needing vigilant attendance. This great new ladle pass-through "feature" completely counteracts the whole point of a slow cooker.
So let's fix it!
Step 1: The Solution
1. It can plug big holes.
2. It is waterproof (handy for for not degrading under constant exposure to steam).
3. It is heat-resistant (handy for the hours of sub-200° cooking).
4. It can bond to ceramics (what the pot's made out of).
Step 2: Getting Ready for the Goop
After you've sanded it, you should rinse the residual powder off with a wet paper towel and dry it thoroughly.
Before we get started, notice that the epoxy I bought only gives 3 minutes of work time. We need to make sure that we get everything ready before we mash it up and the chemicals start reacting.
Thinking a head a little (I managed to this time), I got a bit of saran wrap with oil on one side to help with making sure that the epoxy has the right shape after we've got it in place.
Step 3: Plugging the Gap
Twist off a bite-sized piece of the epoxy and mash it all up until it looks homogeneous in color. (It also starts getting a little warm.)
Now mash it into the gap, and make sure that it's pressed firmly into all the cracks and down all the sides.
(1st picture) Now put the oiled plastic wrap down, oil side to the epoxy. Now we can shape it more carefully without getting our fingers or the lid too gummed up. Try to get close to the expected normal shape, but make sure that it sticks up above the lid-holding rim a little.
(2nd picture) Then put on the lid and jiggle it around a bit, to level the epoxy with the surrounding pot.
Step 4: Done!
If you really care about looks, you could probably touch it up with some black enamel fix-up paint, but make sure it's temperature-resistant.