Fire Breath is pretty awesome. Back before I knew how to DI, I remember getting trapped until I had around 60 damage. Now I can sometimes get out of it before I hit 20 from up close (grab range).
I'm not a great Bowser, but I'm trying to get better with him, so he could be a possible secondary because I like him. But as far as I know, as long as you don't Fire Breath the wrong direction, or too far away, it's hard to punish. It was also a key move in my battle against my friend who mains Shiek....end of the game I had 1 stock left with 140+% damage on Final Destination lol
Last stock was epic. He got me in the AAA combo and tacked on a good amount, then proceeded to f-tilt me repeatedly. I managed to DI out and land my two A jabs. Then he ran to do a dash attack but I got him with f-tilt. When he was coming back I grabbed, d-throw, and used Fire Breath on him and did around 30 damage. I managed to hit him with both hits of a semi-charged f-smash when he was recovering (he did up+B a little too far above the edge). That almost KOed him vertically but didn't, and he tried to d-air down to hit me when he saw me jump, but my u-air hit him the same time he hit me, and he died.