''After all these years, I still look back. . .with wonder.'' So said wide-eyed Kevin Arnold as The Wonder Years signed off in 1993. Twelve years later, we look back with wonder that it's not on DVD (except in meager ''best of'' and ''holiday'' editions). From the first flashback to the finale, Years remained a sentimental journey without the gooey center. Young Kevin faced puberty, the suburban jungle, his ''butthead'' brother and got by with a little help from his friends (allergy-prone Paul and first love Winnie). The series shied away from the quick fixes and preachy parents symbolizing other family fare, preferring a zits-and-all approach. ''A lot of buried emotions got exposed at the end of episodes,'' says exec producer Bob Brush. So where's your sense of nostalgia, Fox? Company rep Steve Feldstein says only, ''We've got it on the schedule, but there are hurdles to clear prior to a firm release date.'' Brush, for one, thinks it's worth the wait: ''The reruns have been all chopped up for syndication. I'd love to see the episodes as they were really done.''