DDG onion should use Single Onion Service (SOS), will be very interesting to see this, if Tor team say it to they, they will use SOS because they are very comprehensive about tor users in opposition of StartPage...
Mentioning the reason for why DDG-onion on about:tor at first before doing anything else is a good idea:
This is feasible since only a very few percentage of Tor Browser users make initial searches on about:tor, thus, its load and performance drop-down should be minimal if this gets implemented.
note: different cypherpunks nym user here than the previous comments.
is this change planned soon? (or ever?)
ironically, since any deviation from the defaults makes one's traffic unique, choosing to manually select the onion service from the search preferences could be argued to reduce one's anonymity
conversely making the default a dot onion provides a great example of a lawful, useful onion service