And i've seen them both hold the world title enough times to know they don't connect
Think the problem Sheamus and Del Rio have is that they're able to talk, so they're given mics BUT the programming and booking has their characters come off as really campy and "on", so they get stuck in that pocket. Dolph kind of has that issue too when he's on the mic. Just really campy and stuck In character. Other guys connect a bit better because they're not hindered quite as much by "character".
It's like seeing someone that can dance with soul and seeing someone that looks like they're counting 5, 6, 7, 8 in their head.
All the Attitude Era guys get so much love because they did a good job in making them seem like regular dudes being exaggerated versions of themselves. Same with a guy like Punk or Woods. Orton has a character with campy attributes that kick in from time to time, which is fine because he connects by being natural other times. Outside of WWE, a guy like Del Rio gets to flow more.