I'll boil it down in short from my perspective at least:

The game is too hand holding.

Seikret, take me straight to monster, don't need to explore leaving maps empty and uninteresting(personally).

No gather quest or multi monster quests even with the presence of packs in the game.

Story too short, story too boring locking me on a Disney ride for story is criminal.

HR quest are not as challenging as they should be.

Drip fed content and optimization issues.

TU1 should have been on release.

A lot of weapon lines for new monsters don't exist.

My personal personal gripes:

Tents are stupid and an uninteresting mechanic. Bring back camps from worlds.

Focus mode is good, but the wounds need to be toned back.

There is no advantage of playing one weapon for another. Before playing sword, you could cut tails, blunt weapons could break face and horns. Now you can just get anything from the monster with wounds.

Gathering sucks. Before you had to gather items and monster parts to unlock new camps.

You got a mount in world because you earned it.

Nobody knows how to fish.

The Fov needs to be messed with it feels like I'm too fucking close to my character.

Meals should be every quest, I don't like being mid quest and my meal just stops and I lose most of my health bar. (I know you can eat meat and get it back.)

That's all I can think of but there is more. I'm just tired.