Going from the addition to the NB Stats thread, Champlain Place is pushing around 505M$/sqft while the other two malls were performing at 448 and 443 respectively.
From the Primaris release, adding Regent and McAllister to their portfolio puts those malls firmly in the middle of the pack property wise. (Regent is exactly in the middle, and only Place d'Orleans separates Regent and McAllister). Most of their properties are in that 450 range, so it does seem like a good fit.
CP's pulling in 505, which would place it 9th on the list, 5 slots above Regent. (and just behind Park Place; whereever that is; don't say next to Boardwalk.

). While it would fit in Primaris's portfolio, it would be one of the higher end properties. While I'm sure they would have loved to grab it, it was probably out of their price range compared to the other malls, for now at least. Who knows what the future will bring?