HobbesMkii said:
I think they're sticking firm to their "Duels is for unfamiliar players" thing, so that's why they avoid cards with more "complicated" effects and deck-building. My bet is they don't want to have something that fully mimics all of Magic for fear of losing customers of the physical cards.
Thing is, there -is- something that fully mimics the physical game:
Magic: the Gathering Online. The program is free to download, and you spend real money to buy virtual starters & boosters. In a surprising show of goodwill on WotC's part, if you amass a whole set of virtual cards, you can have them remove that set from your account and they'll send you the complete set in the mail. It's been around since at least 2004, and my guess is that it makes enough profit and affects physical sales so little that WotC maintains it even if it isn't very popular.