In respect of dual signature, the key word is "green" - this would be appropriate for validated domains such as banks, not necessarily for all hosts.
An advantage of a WoT model is that it is possible to give partial trust to different signers, and set a policy to trust a site once there are enough partially trusted supporters for it. This means that the system need not be fragile to a lapse in a single signer. At base though, you can have something exactly equivalent to the current single-signer model by issuing the root public certificates for the current CAs with the operating system.
An advantage of the web of trust model is that you can incorporate CAs as parties that you trust (exactly as for the current model), but you can also require multiple signatures, which as far as I know is not possible with the current model. You might, for instance, require that two of the current CAs have signed a certificate before it lights up as "green" in a browser URL bar.
First of all, you're forgetting where the Bible even comes from [catholicapologetics.info]. The Bible is not the sole rule of faith, was never intended to be...
The church existed before the New Testament was written - yes. However that does not mean that the Roman church was responsible for its production, or the that the various writers agreed with the emerging traditions of Rome. The gospel of Matthew, for instance, appears to have been written by and for Jewish Christians, and in ch 15 (part of the Sermon on the Mount) clearly states that all of the existing Law still applies to Christians - a view diametrically opposed to that of Paul (Peter appears to have swithered on this question, according to Acts).