I'm hyped for that Side b honestly, it's "option select" the move, and there's nothing short of insane that can be said about that. Not to mention the doubles potential.
Bair looks to have low landing lag (kinda crazy considering the size and utility of the move) and he/she seems to have a fast ground speed like Marth and Roy. All of the tilts don't really seem to have much range but they're decently fast and may benefit frame traps (which get nuts when tossing in stuff like the stunner and the lunge). Dragon Shot is where things go crazy for the character I feel. Here's a character that can stun you, combo that with a pin, and cancel that (Cancelling also forces a tech, it seems) into more mix ups and stuns until the enemy is off stage. I think Corrin might be a legit vortex character in the end, if my assumptions are correct and has an even decent grab game. Also the projectile speed is way faster than I thought it would be and that scares me. Those specials are very very good.
Character wise in Fates, Corrin falls into the category of the "way too nice for their own good" lords populated by Eliwood and Marth. He/she also undergoes different degrees and kinds character development based on the route. There's also some interesting aspects here and there. Not the best lord and not the worst lord in the series and I like him more than Chrom actually in terms of character development.
Music wise, I'm really excited for the instrumental remix of the Main Theme of Fates, but I really love the JP version and hope they didn't change the final bosses theme to English, it's so fantastic or at least allow dual audio for that.