It is a little bit crowded as you noted. And when it's in there, the bag doesn't slouch the way I love it to when it's empty.
But my work laptop is a 15" MacBook Pro! So I'm screwed for that machine - when I have to take it to client meetings it gets stashed in my Mulberry (oversized) Alexa. They are supposed to be getting me a smaller 13" MBP at work but I think it might be too heavy for any Bal.
Personally, I wouldn't carry a MBP in my Bal, because I find it too heavy. The max I'd put in it is a 13 inch MBA.
Perhaps you could just get a laptop bag to put the laptop in? There are some pretty nice, inexpensive bags for MBPs. I used to use Fabrix cases with added handles so I could handcarry the laptop, and dump the charger into my bag.