At this year’s GDC, Stefan Engblom of Supercell talked about the team’s approach to card balancing in Clash Royale. While he pointed out a few areas where collecting data can be useful, he also emphasized that it’s clearly not everything. Instead, he underlined the importance of flexibility and quick iteration when trying to find the fun. But most of all, he recommends every creator to play their own game over and over again during development and after, to gain a deep understanding of and feel for the gameplay.
Watch the full talk in the GDC Vault: http://www.gdcvault.com/play/1024272/Quest-for-the-Healthy-Metagame