Yes, I know the Map Editor is the red-headed stepchild, and so far down the priorities list it actually sticks out at the antipodes. Still, bear with me (it's the forum for that):

One (of many) aggravation things about the JA2 map editor is the silly randomization of item values it forces on us since the very beginning. While initially it made some sense ("Stupid casual gamers need some random decay to spice things up"), we're long beyond the "casual gamers" public, and we don't need their random damage generator "to spice things up".
People using it nowadays are exclusively dedicated die-hard JA2 modders, who most definitely know what level of quality and chance of being there any item they place should have.

So I'd suggest to make the randomization optional. If you turn it off, the editor simply keeps the last value in memory. Example: If your last can of vegetables was at 84%, all following items you place will be at 84%, until you manually edit one to give it another value, in which case that new value will be used henceforth. It would be nice if this happens for all numerical values (quality, amount/ammunition, chance of existence).
It kind of already happens for some values (like chance of existence), so I think it shouldn't be too difficult to implement.
Turning it off could be a run parameter ("JA2_8796_Editor -norandom"), so no GUI change needed. People would make that command line into a shortcut and run the editor from there.