The uniqueness of the miraculous signs in John does not simply lie in the fact of the occurrence of the miraculous. It could also be seen that Jesus gained a following, with people believing in Him, His message, and His movement, through the witnessing and reporting of miraculous signs. Others before Jesus (and after Him) had and would gain substantial followings as well. However, in contrast to Jesus, their followings often grew with reports of their rebellious and subversive activities (Jesus was shown to be subversive, but in a more subtle manner), their incitement to violence against their oppressors, or their military exploits against the vaunted Roman military machine. Jesus’ following achieved no growth along such lines. He certainly did not go about achieving His popular support in the usual or largely expected way.
Though John the Baptist is reported to have been caustic in his speech (though not in John’s Gospel), what was said of his cousin (Jesus) could also be said to be true of him, as he did not gain his following along the lines of the usual or expected means. How could he? Had he engaged in overtly revolutionary activities, he certainly could not have heralded himself or have been heralded as preparing the path for the type of messiah that Jesus presents Himself to be, nor would Jesus have aligned Himself and identified Himself with John’s movement (the signaling of a new exodus for Israel, and through Israel for the world) by undergoing a baptism at John’s hands.
The regular references to Moses in the Gospel of John, whether those references be explicit or implicit, are both an adjunct to the mentioning of miraculous signs and a reminder of the way in which Moses went about proving that he was charged with representing the covenant God to His people. It must be said that Moses gained a following, though the following was not gained (as he may have hoped or expected), when he raised his hand to kill an Egyptian that was abusing one of his fellow Israelites. That action merely sent Moses into his own period of exile, possibly delaying the Creator God’s plan to deliver Israel from their Egyptian bondage.
Initially, Moses gained his following through performing miraculous signs, which is what he was instructed to do by the Creator God when he returned to Egypt with the demand to “let My people go.” When Moses had questioned God as to how he was going to convince Pharaoh and Israel that he spoke for the God of Israel and that he was the vessel through which that God was bringing about the deliverance of His people, Moses was provided with a series of miraculous signs to perform. The book of Exodus records the performance of these various signs. This point shall be taken up again shortly.
Returning to the text then, the author seems to take pains to hammer home a point previously and repeatedly made (this would have been second nature for his audience, but not so much for members of a modern Christian culture which has a tendency to separate, divide, and pluck passages and stories from their setting and examine them in isolation), which is that the Gospel narrative must be heard as a unified presentation, rather than presented through selected portions of the narrative.
While it is certainly possible and appropriate to elaborate on circumstances, situations, and statements, such things demand to be considered within their wider context. Any statement by Jesus, or the author for that matter, that is pulled out of the text and examined on its own without being placed in its appropriate theological, soteriological, sociological, cultural, political, and eschatological framework (at the very least), will end up as nothing more than an ingredient in a recipe for fallacious and anachronistic exegesis.