They wanted this to be a separate game soooooooo bad. Getting rid of every aspect of Rise's core identity kind of sucks (namely the poems and the vocals in the music, as well as the rampage quests, monsters, and weapons, the former of which I kind of liked, the middle of which would have been fantastic in G-rank outside of anomaly quests (which suck so bad and are essentially padding for the postgame) and the latter of which I loved) and moving from the friendly people of Kamura to everyone mostly acting cold except Bahari was jarring. They also completely fucked Shagaru Magala, one of my favorite fights of 4th gen, by making it 1) not an arena fight like it was meant to be and thus making a majority of its attacks feel much worse to play against as well as making it feel less eventful, and 2) have a more generic moveset (not every elder dragon needs a laser beam). And I'm sure the new silkbind attacks for other weapons are fun but as a hammer player the new silkbind attacks basically just being "have more dps" was pretty boring. Still pretty fun overall since it's a monster hunter game though.

Sunbreak refines Rise's mechanics with some nice quality-of-life improvements, and swapping out Anime Feudal Japan for Anime Western Fantasy is a nice change-up. There's a bit more emphasis and effort put into the writing, which makes it disappointing that it ultimately takes no risks. Also disappointing that all of the new, interesting mechanics are basically all superfluous because of how damn easy the game is. Still, the monster designs are broadly fantastic, the new areas are fun to explore, and the slight extra emphasis on environmental interactions is sorely appreciated.

When I hear people saying how Sunbreak isn't Monster Hunter I always check for two things, and usually at least one of them checks out:
1) They're World fans
2) They "used to play Freedom Unite back in the day with their good ol' PSP"

Don't fall for the common accusations, Sunbreak is the absolute pinnacle of Monster Hunter combat, paired with one of the best monster rosters in the series: you've got Astalos, Primalzeno, Gore Magala, Lucent Narga and many other stupid good fights to learn and get your new hat out of.

A thing I usually criticize about Iceborne is the sets balancing: you want to do GS? Fatalis. CB? Fatalis. DB which are literally elemental killing machines? Fatalis, elemental sucks ASS in that game. Pair those weapons with a full Fatalis armor (or one AT Velk piece if you fancy) and slot in the decos you just grinded 100+ tempered Teostra for and you're good to go!

Now here, things are different: any weapon has so many possibilities, in terms of both elemental and raw damage and skills you want to implement to your playstyle. Berserker, Strife, Blood Rite, Buildup Boost; you name them, they got them.

My very reasons for it not being 5 stars are bond to the fact the expansion starts VERY slowly, like 3 stars worth of missions are mostly boring fights you already did with a fire/blast variation of a newcomer you fought in base Rise BUT the second you slay that damn Astalos the game just starts to ramp up and it NEVER STOPS.
My other reason is the fact once you get to the endgame it gets a bit disorienting for all the stuff it introduces you, so it takes a while to understand that + it slows down quite a bit because the real juicy stuff starts after you reach MR100, with Scorned Magnamalo and the Risen fights which are just that good and challenging!

Man I love this game, what a wonderful life-ruining experience.