This is respectively speaking. There is the assumption that tanks will be doing significantly less damage and no evidence to support this and the provided source doesn't claim this. It will be a small difference at best. Considering 90% of the players in this game aren't playing there classes at 100% ability anyhow I doubt it will be of substantial effect to anyone outside of like the 90th percentile of their class attempting to min/max stats and rotation parsing. Honestly outside of Savage raids these changes aren't wholly relevant. The changes were specifically to deter the necessity of pentamelds for raiding.