I had watched this, and quite enjoyed your commentary.
I don't quite agree with you about Link's D-tilt though, even against a slow character like Bowser it's still not an underrated or good move to throw out in neutral. It's amazing as a finisher starter on FFers but at 14 frames you need to plan ahead for it or get them on recovery/lag punish.
Overall Bowser is a fun MU to watch, but compared to spacies and other top tiers who can smother and obliterate Link there isn't much to be learned. Link can lterally just jab and Fsmash (mixing up 2nd hit) and Bowser can do nothing, if he goes above you he's screwed with Link's Up-airs. And that's not even mentioning projectiles yet.
I think this should be a very very easy MU for Link since Bowser's Up-B OoS should never threaten him with good spacing and projectile usage.
That said Synett is a really good Bowser, seems to have learned fast but is technically sound. He used all Bowser's optimal moves in the right spots and played the neutral much better than you did, but Link having the favor in this MU edged it out for you.
Would like to see your commentary against top tiers if you get the chance, keep up the great work. I'll be following.