People will always express their "safety" concerns when there are children involved, we also received a lot of crap about our Bullitt. The most important thing is that you feel safe and confident about it, if you keep second guessing you'll never be able to take the kid out for a ride into traffic
If you feel safer with a more protective car seat, do it. If your wife feels safer with a (removable) roll cage bar, do it. It might not look pretty, but once your offspring is a bit older, you can still remove it afterwards. I hate riding around with the canopy on our Bullitt but it keeps the kid out of the elements and has quite a sturdy "roll cage" design.
Also, you can never account for other people doing idiot other people things, but just as most of us on here, we ride bikes enough to estimate traffic situations and act accordingly.