If you're going hard into incarnum grappling, it only takes one feat (Double Chakra) to get both Girallon Arms (+2 and +2/essentia) and Kraken Mantle (+1/essentia + Constrict) for a nice x1.5 to your bonus and some damage. A straight Totemist grappler would probably grab it at 12 level (after getting Double Chakra (totem) at 9th). If they start with 12HD, the Kraken can't even get Open Lesser Chakra until ECL 15, and can't get Double Chakra until ECL 21 even if they go straight Totemist (at least at this point they'll have naturally unlocked the lesser chakras), and they'd probably want to spend that feat on either Open Epic Chakra or Double Chakra (totem).

And yeah, you don't really need to bind Girallon Arms to the Totem like most Totemists, but it is still 4 extra natural attacks for attacking, holding enemies, and constricting. It's a strong contender for the totem bind even on the Kraken.