3.5e just had some much room to explore. Yeah, some parts sucked or didn’t make sense, but I think that really led to some interesting characters and fun moments in games. I haven’t played 5e much precisely because it’s so smooth in comparison.
Why would anyone want their diplomacy interrupted, even as the one being affected? It’s not like diplomacy is some evil spell. A successful diplomacy check means you were able to have small talk, relate, and do all the normal things strangers do to put each other at ease. You don’t “defend” against diplomacy!
Imagine trying to agree on a treaty with some jester interrupting every 54 seconds…
I will never not be jealous of the pure joy a cat must feel stretching.