So I take it you've read every line of pfSense, OpenWRT, and the Linux kernel (or whatever else you use)? Your point 1 is utter nonsense for most of us; we don't have the time or abilities to vet all our system infrastructure. To be clear, I prefer open source too, but I don't fool myself that I'm going to discover or fix any vulnerabilities in my router.
"Wifi is very exploitable" seems like FUD as well. For one thing, nobody further away than say 100m is going to be able to break into your WLAN, even if it's totally open. That makes your ISP connection far more dangerous, unless maybe you live across the street from a nest of evil-minded hackers. Sure, it's a good idea to be using strong passwords, getting off of WPA2, etc, but I don't believe that for practical purposes a router that has wifi built-in is any less secure than one without that.