The UUU cost on Archmages Charm is the biggest limiter on how widespread its usage pattern will become, since only U/W Control decks and possibly Mono Blue Tron builds with Urza are likely to be able to easily support the color requirements
In general, the problem with expensive cards is that if you cast them and your opponent is able to answer it, you are in trouble
Its potency lies in its ability to provide unparalleled card advantage, enabling players to access more resources and options
See rule 107.4e.) Effects may change an objects color, give a color to a colorless object, or make a colored object become colorless
And then we have the booster packs
And if we cant shut down the card draw altogether, well at least find ways to punish it