Even if there was a viable single rider line, it would not move very quickly--just as the one in DCA doesn't. The ride loads in such large groups that there are many ways for the grouper to fill rows. Figure that, at most, one out of the three rows isn't perfectly filled, because if there were two rows, the grouper probably could rearrange the parties in those rows for another party of two. So, you get (at most) three single riders pulled per cycle. End result? Glacial single rider line.
For the next while, you'll either have to get there first thing, or grab a fastpass if you want to avoid the lines. That's less true in DCA, but only because DCA has lower total daily numbrs---practically everyone through the turnstiles in either park has Soarin' as their #1 goal.