Jon Davison says in a recent interview that the new Yes album, Heaven & Earth, has 8 tracks (plus a bonus track for the Japanese CD). Let's presume the album will get a vinyl release, so that limits the overall length. What does this mean for song lengths?
Well, Yes and Time and a Word had 8 tracks each, the longest at 6:54 ("Survival"), the shortest 2:06 ("Clear Days"). The Yes Album only had 6 tracks, but Fragile had 9 (with 3 tracks under 2 minutes and "Heart of the Sunrise" at 10:34 + reprise).
The next few albums all had rather fewer tracks (3, 4 but a double, 3, 5), but Tormato also has 8 (up to 7:47 for "On the Silent Wings of Freedom"). Drama is a short album and just 6 tracks, but 90125 has 9 (up to 7:39 for "Hearts"). Big Generator is another 8-tracker (maximum 7:37, "I'm Running"). Union, on vinyl, was I think 13 tracks (including "Miracle of Life" at 7:30).
So, actually, 8 is the commonest number of tracks on a Yes album (from the vinyl era). Fly from Here has 6 or 11, depending how you count ("Into the Storm" at 6:54 is the longest if you don't count the "Fly from Here" suite). The longest track on one of these 8-piece albums is only 7:47 ("On the Silent Wings of Freedom"), but Fragile squeezes in one track over 10 minutes out of its 9. Generally, we see a lot of the longest tracks being around the seven, seven and a half minute mark.
Wild speculation, but there you go.
UPDATE: A new Chris Squire interview has more. He describes "three [songs] that are on the longer side, nine-, 10-minute sort of long songs." But that can't leave much room for the other five tracks.
OK, presume they long-uns are 9.5 minutes long each. Three of them adds up to 28.5 minutes. If we're still presuming a vinyl length to the album, then total run time will be forty-something minutes. Fly from Here was towards 48 minutes, but albums like Fragile, The Yes Album and Tormato were under 42 minutes. Let's say the new album is 47.5 minutes long, then that would leave 19 minutes for the other 5 tracks on the album, or 3:48 on average. That's short. That's shorter than everything except "Cinema" on 90125, shorter than everything except "Holy Lamb" on Big Generator.
So, maybe we have something that looks like Fragile, a bunch of shorter tracks (the five "solos" on that album go up to 3:00 long for "Mood for a Day", plus "Long Distance Runaround" is 3:30) and a few longer ones ("Roundabout", "South Side of the Sky" and "Heart of the Sunrise" all over 8 minutes).
Squire also described how Davison "worked with the other four of us on a couple of tracks each", so no solo tracks like on Fragile. Should we take Squire's quote literally? Will the credits have 2 songs that are Squire/Davison, 2 that are Howe/Davison, 2 that are White/Davison and 2 that are Downes/Davison?
UPDATE (25 May 2014): German Amazon gives the LP release as being two discs, so all those assumptions above go out the window.