Its not really a vulnerability if you have it locked. Its a vulnerability to people like me who close up everything at sundown beat tired and forgetful. You should be fine but that is a common entrance point for Raccoons but you should be fine. I have 2 coops (out of about 15) that I made egg doors and I forgot to lock them a couple of times and now they stay locked full-time. I reach in the long hard way to retrieve eggs. Never had an attack come through them because I was lucky.
We'd ALL like to go larger and taller ... 'cuz more is better, right? I had to do a serious downsizing this fall, because I can't go "larger and taller," yet. I hate Chicken Math! 
