I think one of the major areas they might struggle in is decent prose. I expected the new 538 to have lengthy and interesting prose in addition to data, but most everything has been a slog to read so far. Maybe I've just been spoiled by Grantland, but I really hope it improves.
Yea, that's true. Grantland has truly excellent writers, whereas 538 may have been looking for something different than pure writing ability. Still, guys like Kirk Goldsberry could easily write for 538 in terms of technical competence.