MeCho wrote:
Now how about gain 10 wall instead of gain 10 tower or wall and lose the Legend keyword and summon HIGHEST cost discarded card
The latter just begs you to build a deck around one or a few cards to summon them every time you pull a zero cost uncommon and increase your draw, thus no. Another card might do as such. Seer is not intended to be.
As for the wall and tower, the uncertainty makes the card worth
less, not more. You might be up against charge cards, or you play a Runic deck - situations where the tower gain is the exact opposite of what you need.
To be frank, the legend keyword is there for two reasons: 1. (and you have noticed I do as such often) The card fits a theme, and 2., The Legend decks most of the time end up as just piles upon piles of unicorns. Some variety is helpful.