Sunbreak is extremely good, the ability to have two switch skill loadouts and switch between then in a second is game changing for some weapons. I don't play long sword so I can't comment on what it does for that weapon though.

The new monsters are super fun fight and it requires you to eventually get very good at knowing your op counter bullshit to win the final monsters they added a year after release. Maybe some people don't like that but I had a blast with dual blades.

Replaying on ps5 now trying to learn charge blade.

I had a lot of fun with the tools it gives you such as the beforementioned Skill Swapping. I did not play World, so I can't say what is evolution and what isn't, but the endgame monster (the big big big boss, not the final monster in the string of post-game releases) was a fun little spectacle. They don't do Rampages at all, which while I found them charming I thought them unnecessary and others disliked them. They drop the Japanese aesthetic, which is a little unfortunate, but the hub is good and continuous. The new maps are cool, lots of exploration potential.