Building a well-rounded deck is always, always Step 1. That doesn't mean you shouldn't use conditional cards, it just means that if you're going to use them, they should have some kind of special synergy with the rest of your lineup. For example, Sting and Baba are better off in a Freaks half-deck, where landing first-turn poison means they can become excellent damage denial cards.
You shouldn't judge someones skill purely bade of their win loss ratio. There are many factors that could unfairly influence that, not to mention you tend to grow as a player and become better as more time goes by. Although I do give you props Lingod 1304 ELO with a deck that has Sting and Kalder in it ain't easy.