Congrats! Raven was also my first +10. LnD6 makes him too much of glass canon. I pretty much run the same build and it works just fine. All you need now is to upgrade to Flashing Blade 3
LnD3 is definitely overkill and that is why I would do it but fury is probably better. I have been working on my Raven too, I'm only at +3 because I'm also building up a Soleil and Titania.
A wave skill would probably be better, atk or speed would be prefered, but even a defense one would be dope, aaaand I'd honestly recommend heavy blade over flashing, for the sole fact that more units can use the seal