maintain the group America's smooth, upbeat wave of studio pop here. Good melodies; competent, if bland, vocals; and a well-oiled pace running from cut to cut - that's ''Your Move.'' Yet, I was disappointed. Admittedly, America's folk/pop past has been anything but heavy-hitting. With their brand of often mildly melancholy pop tune and a style inspired in part by Crosby, Stills, and Nash, they scattered a fair number of listenable hits around in the '70s - songs like ''Sister Golden Hair,'' ''Tin Man,'' and ''Ventura Highway.'' (They haven't come up with a winning tune since the departure of member Dan Peek in 1977 - which, of course, is hardly an indictment.) But somehow, this LP was just too bland, too sure in its mastery of the pop tune to satisfy me. There's a certain emptiness, a lack of conviction that's needed to climb above simply being an album of tunes. The two remaining founders of America - Gerry Beckley and Dewey Bunnell - have, for the most part, handed over the writing and much of the creative responsibility to Russ Ballard, who must be held partly to blame. The pleasures on the LP - ''Love's Worn Out Again'' and ''Tonight Is for Dreamers'' - is backed up by an unfailing group of other tunes. Nothing fails, that is, but in the end nothing really succeeds, poking its head above the musical sameness.