Even though a lot of posters in this thread are putting him in the attacking midfielder position, Dybala is not a typical #10 for a 4-2-3-1 — he's more of a 9½ withdrawn forward (like Griezmann but without the defensive draft). A double pivot midfield with Pogba is defensively shallow over the course of a season because he's not a stereotypical central midfielder with regard to defensive positioning and workrate, and adding Dybala to the equation at the attacking midfielder position will limit both players (on top of being structurally brittle).
If you consider Dybala when he evidenced some of his performances (like vs. Barcelona in the Champions League), he was pretty much a support striker alongside (or slightly behind) Higuaín, with Mandzukić putting in a shift on the left flank (and sometimes arriving into the box) and Pjanić/Khedira playing in conservative roles as the DLP + defensive/box-to-box midfielder coupling:
https://spielverlagerung.com/2017/0...ing_wp_cron=1564205866.2880189418792724609375
United will find it easier to accommodate a more traditional attacking midfielder in the current 4-2-3-1 — and Dybala isn't one (for added context: Allegri initially forced him to play deeper at Juventus but that was grave misjudgment and Dybala's performances declined considerably, so there's already a precedent). To get the best out of Dybala there are only 3 options, IMO:
- Diamond or 523/532 with Dybala as the SS (not the #10), but we don't have the wingbacks for that setup.
- 4-3-3 with Dybala as the center forward (not striker but a False 9 of sorts).
- 4-4-2 with Dybala as the support striker, but this won't be ideal if we use Pogba as a central midfielder.