I'm curious
1) Is it the collectible nature of the boosters (as dm4hire points out) that is the problem? Would a non-random expansion deck "fix" the game? Or, no new cards at all, except perhaps in later "full" expansions like "Famine in Far-Go"?
2) Or is it the actual use of the cards in play, making powers and gear random during the game? Are randomly drawing cards during the game problematic, but okay during character creation? Would randomly rolling on a table be better (basically the same effect using a superficially different mechanic)?
For me, the only issue I have with the Gamma World cards is their blandness. Not necessarily the powers and tech printed on the cards, but their visual appeal. I have the same complaint about the cards used in the new Ravenloft board game. For a company that makes beautiful cards for their flagship collectible game, Magic, why do we get such boring and dry looking RPG cards? I even felt this way about the power cards that were released earlier.
Obviously commissioning quality artwork for each card would raise production costs, but would it result in more sales? I'm guessing WotC doesn't think so. Still, as using cards in RPG play is a relatively new experiment for WotC, I hope they experiment further next year with the release of the D&D Fortune Cards and use evocative visual design with beautiful artwork. Heck, I'd even prefer the use of "recycled" art over none at all!