The additional mana is produced by Roxanne, not by the artifact token that you tapped for mana
The deck tends to struggle vs control decks/decks that try to make the game as long as possible, since at some point drawing cards like Force Spike or Mother of Runes is similar to skip a draw step, and usually control decks have a good way to counter/deal with Aragorn itself
Four loyalty is a big chunk to get through, especially if it is early in the game
You don't need to draw Spider Spawning for it to win you the game
Red is the best mana acceleration color, giving out huge one-time bursts of mana for a comparatively low up-front investment
The Chromatic Challenge, a deckbuilding exercise in which the person creates a deck for each color combination, had been around for a few years by that point but couldnt be completed until November of 2016