I agree we should get the keyboard right, and I think it would be nice to have a lot of "free" keys, which do not have any AltGr printed on them, but which can be remapped. One of ED's implicit design criteria from the first post, however, seems to have AltGr's printed on everything.
I put some stuff in green, which I think doesn't need to be printed on the keymats, but ED may want to put in the umlauts, even if they are on the "reasonable" keys:
http://www.keyboard-layout-editor.com/#/layouts/777cd949304cf7f8425ac5ef8f4b9684
I'm trying to put symbols like []{} on keys that typically don't have an alternative form for international layouts, but Grench'ifying things for extra free keys. Still no more than 3 prints per key, though.
I know some things end up on the "wrong side" of the keyboard, but this is to keep room for some of those free keys I'm talking about, as well as making it easier to chord common mathematical expressions (<=, +=, -=, :Enter, etc.).