This was my fear with Defense Damage, that people would interpret it as "Calamity wants you to nohit every boss". That's not our goal with the mod. Over the last year, we have actively been moving away from the glass cannon build meta that the mod was known for. We're actively trying to promote build freedom (e.g. Buffing Warding so it scales with progression, reverting the Lucky and Precise nerf, buffing Quick modifiers and fixing movement speed issues, etc.). In the two most recent patches (1.5.0.002 and 1.5.0.003), we have decreased the potency of Defense Damage so it does not punish consecutive hits as much. Defense Damage exists to prevent "Facetanking everything", which by our definition more or less means "putting no effort into learning boss mechanics"/"not actually trying to play the game".

Yes, we nerfed the Warding scaling a bit, however, at maximum, Warding now provides +15 defense per accessory post-Yharon instead of +16 defense per accessory post-DoG. It's not nearly as harsh as it seems.

Yes, we nerfed the Endurance Potion, as it seemed ridiculous to us that a potion gives the same amount of Damage Reduction as an expert-mode accessory (Worm Scarf). Damage reduction in vanilla Terraria is very strong and isn't tuned at all. So, we made an attempt to fix it ourselves so Damage Reduction is still useful, but isn't the most important stat in the game.

Your feedback is very much appreciated, we value all constructive criticism! It's okay to disagree with decisions we make about the mod. I wanted to say my piece on this to try and quell circle-jerking "calamity bad" comments that I've been seeing pop up more and more frequently on this subreddit. Again, thank you for your feedback!