Actually, I don't think there's anything new asdf that warrants a feature, so I'd add a uiop feature only (and uiop has evolved enough since 2.27 that a feature could help, especially considering that at least quicklisp distributes uiop without asdf). I believe uiop/driver.lisp is the correct place for the pushnew.
OK. Should we at some point define a stable UIOP feature set, and just bump to 3.0 as a new stable point?
I suppose whenever you release 3.2 (hopefully this year) is the best time to decree that whatever is in UIOP is the new stable point, and then to apply "usual" deprecation policies to any API change.
Of course, it would be nice if deprecation support functions were made part of UIOP before this happens, though not strictly necessary.
—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org During the Bikini operations, a discussion arose as to what weapons would be used in the next war–atom bombs, germs, rockets. “I don’t know what weapons will be used in the next war,” a young Army lieutenant interrupted, “but in the war after the next one, surer than hell they’ll be using bows and arrows and spears.” — Joe Laitin in Frontpage, 1946