Walking to the D gates should be no big deal, we did that for years.
And honestly the bootleg at gates C8/10/12 was always a mess of people and not enough room. Of course D gates had the habit of filling the entire walk area much like C2 used to do.
As for the AC moving to Cheers. I tried that place once years ago, once was enough. I don't recall how it was setup, but more than likely a lot of remodel would need to be done to add a desk, restrooms, etc. But once done, it sounds like that would work fine.
Connecting D and E - I just don't know if there is a lot of need for that. My only reason for ever wanting to get from A or E to C/D was to use the AC club before flying on someone other than AA/TWA.