If I could add my $.02 I would say kudos for thinking outside of the box.. While im not really a fan of front pocket wallets I'm sure there's some people who like them.
I would firstly consider using a lighter weight leather to keep the bulk down and also I think you could remove the back piece of leather from the ID window, I feel like its unnecessary and would function fine with that window sewn directly to the inside wall .. another observation is it seems like there's a lot of extra leather where it could be removed but I guess that's what makes it a font pocket wallet ? lol anyways keep it up !