Well, when i create a deck, i almost always have the gatherer and essentialmagic pages open to help me search for the card i'm needing; Because i have the idea "i need a card which can do X thing and for aprox. X mana cost, but i dont know the name, set or even if such card exists". So, in gatherer and essentialmagic i can search for cards by their rules text. For example, a card with a trigger "whenever a creature enters the battlefield", actually, we can't search for a card with that specific ability, or cards for example with cycle, or cards with a "draw" or "discard" mechanic. You know, abilities without an specific word like "flying", "trample", etc.
I'm not saying to add all those possibilities to the abilities search, but more like the sites mentioned before: Input a rule text and the game displays the cards containing that rule text. It's more like search for a text within the primitives file and then display the card containing it. + All other filters, like colors or casting cost.
I know the psp may do such searches really slow or even could not have enough power to support so many features, and dont have the best design for input text. But the newest android phones may have it... You know, as this game evolves and grows, it will need better hardware to support it's features.