One thing that tends to be weak in strategy games is "opponent's choice" effects, where an ability has multiple possible effects and an opponent chooses which is resolved. Usually, each effect is stronger than what you would normally get for a card with that price, but in practice these cards are often quite weak.
For instance, the Magic: the Gathering card "Book Burning" looks quite strong in theory, as it either does 6 damage or mills 6 cards (both strong effects that might well be worth more than the card'... (Read more)(Click to expand thread. ⌘F to Expand All)Cmd/Ctrl F to expand all comments on this post
I wasn't linking to that for the 5/5 star rating - there are zero votes.