I haven't done a lot with blueberry. Hitt and Letitia, have way more expertise with it than I do; so I would readily bow to their experience.
But, just as general observations go...
-- 29% of the total flavoring (4% of 14% total) of Bavarian cream seems
waaay too much to me. If I really wanted a cream note to this; I would more likely look at 0.5-1.0% FA Vienna Cream. Or, if I was looking for a "fluffier" cream filling/topping; maybe 0.75-1.0% FLV Whipped Cream.
-- Having both cookie
and cake elements seems like they
could be at odds to one another ('moist/spongy" vs. "crispy/crumbly"). I personally would choose either/or... not both.
-- I like to boost CAP Sugar Cookie with 0.5-1.0% INW Biscuit to make it more "cookie-ish"/crumbly.
-- I do find blueberry (the few I have played with) benefit from the addition of a small amount of lemon (SC/ECX Lemon would be my choice). Again, somewhere in the vicinity of 0.5-1.0%. Can add "pop" and brightness without being identifiable as "lemon."
-- A small amount (0.25-0.5%) of FA Forest Mix can "darken" (make a bit less candy-like) blueberry. While addition of a small amount (depends on concentrate used) of Raspberry will "lighten" the blueberry "oomph," without sweetening or making more candy-like.
-- Low percentages of a Pair (0.25-0.75%) can be useful for adding juiciness, without much altering the blueberry profile.
How any of this might be beneficial to Hitt's recipe... I have no idea. I think he is on the right track... getting the core of the recipe the way he wants it
first. And, only then, add the tweaks and embellishments to take it the rest of the way, and only as/if needed.
I have wrecked too many recipes to count by trying to do too much right out of the gate.