I second this. I love the single-file rockets. The two-abreast seating just makes it feel that much more like any other mundane roller coaster. The single-file seating is relatively rare among coasters these days (and thus feels unique), and also helps the ride feel much more visceral -- there's nothing on either side of you (or above you) but "space" flying by. This is especially true in the first seat, where you feel like you're on your own private ride.
I can understand how side-by-side seating might be better for parents riding with small children who might be nervous, but other than people in that subgroup, I'm always surprised by how many people clamor for the MK's Space Mountain to have two-abreast rockets. In contrast, you hardly ever hear anyone insisting that the Matterhorn Bobsleds or DL's Splash Mountain should have two-abreast seating. (And I also think that those attractions benefit from the inline seating, and shouldn't change their ride vehicles either. Although the MK's and TDL's Splash Mountains have better effects and a better-conveyed story, I much prefer the single-file logs at DL. To me, a "log flume" just isn't a "log flume" with side-by-side seating.)