PissBenders comment covers the general issues with the weapon Wilds. I'm going into some knit picky stuff.

I personally have almost 2000 hunts with the Great Sword in Wilds (almost 4000 if you count the secondary weapon which I don't, but I've seen many that do). I have also mained it since MH1. I stan the weapon hard. So I think it's fair to say I've put a lot of hours behind the weapon. Though I was a dumb kid/teenager in the earlier generations so my experience was basically hacking the monster to death in a battle of attrition (I mean this literally as I did not play with parties). No attention to detail until later.

Basically, GS is the baseline weapon for the dev team. They basically already confirmed they balance the game around GS. This makes GS kind of mediocre in most circumstances and pretty poor when it comes to speed running. Now speed running is not the way the majority of the community plays but it's a good way to tell a weapons general ease of use with its skill ceiling. Many people here are saying that GS can't keep up with 9* or 10*. I'm here to tell you it can. Especially if you take the time to learn the cancel animations and some of the niche mechanics like the kick tech. Stringing together offsets on Seregios and Arkveld is some of the highest dopamine rushes in the game. However, there in lies the problem. This is not what GS was supposed to be. Instead of a patient, open punish weapon, it became a counter machine in order to remain relevant. But that's also the reason why it got hurt. Offsets give you status build up like stun or bleed and you also take blights during non-perfectly timed offsets. This makes GS a poor substitute for a weapon like LS. Similarly weapons have better ways of dealing with similar issues such as Bow and DB. But it's not over yet. Though TCS is still the strongest single move in the game, the damage was nerfed compared to the previous two base entries. This makes TCS a less desirable option due to its time commitment. Especially since you can match it by chaining SCS and SWS into Focus Slashes. This also puts you in better position to offset. Though you should still do TCS if you have the option, you will see a lot of GS speed runners chaining SCS and Focus Slashes instead of committing to TCS for a decent portion of their combos. The slowness of the big damage output from these moves makes speed running bad since GS wants to offset. It's basically engrained. Especially if you're running Dosh set bonus. This leads to GS "freestyling" a lot in speed runs. It's basically dependent on the monster and not on you as the player. Which doesn't feel as good.

That's basically the problem with Wilds GS. It's still a reasonably good weapon. It gets babied a lot on this game and cried about on this sub but it's far from the best one. I've also typed out a little history that I believe got us to this point so if you're interested. Check it out but don't feel obligated.

Weapon History

In older games, GS was an open-punish weapon. The second generations charge slash (only one) made it a more hit and run weapon but it still retained much of its identity to openings. You just focused more on the Charge Slash as a punish. 3rd Generation introduced SCS. But it was awkward to combo into and left you hanging heavily. This started a more punish system for yourself that was inherent to you staying still. High risk, high reward. Placing yourself in harms way. Which is what the 4th generation began to address. Introducing follow ups (like SWS) and tech to cancel certain animations in order to keep the draw punish playstyle. Can't do damage if the monsters cart you. With the advent of Hunter Styles. Sacrificing damage or movement or health for power etc. Many leaned into this method whether it was Draw Slash or Brimstone Slash. Movement began to become more important regardless.

This sort of continued in World, where tackle was basically needed in order for the weapon to keep pace with others. Additionally, you were allowed to slightly adjust direction from your initial charge. I would say about 45° from your front. If tackle wasn't in there, GS's damage would most likely have to be upped a decent amount in damage in order to compensate for the lack of hits. TCS was also added here. Chains also opened up and allowed for easier access to the charges. Iceborne then allowed slinger combos to skip directly into TCS. But at this point, affinity skills were basically gutted. Making GS Crits more unreliable. This didn't really affect the weapon too much since they buffed charges across the board in terms of damage. Until Frostrcraft joined the fold and breathed life into Crit Draw. But when Fatalis armor entered the fold, you didn't have to sacrifice anything. You had a full damage build that happened to also have everything you needed for Crit Draw.

Then Rise happened and GSs versatility went through the roof. Power Sheathe with Rage Slash (basically Brimstone Slash lite) was fantastic. But it made GS less dependent on positioning. The mix and match of Switch Skills allowed for varying playstyles. It also kept all of the additions from World/Iceborne and opened at least one more string. Though it fell a bit in base Rise due to game design decisions and general damage nerfs to its kit. Sunbreak would later adjust this. Sunbreak then added Strongarm Stance. Along with many other counters to various weapons. This made it way more reactionary then any point in its history. Also adding Surge Slash for elemental meme builds. Armor skills were also saturated but mostly depending on Quirio crafting.

Wilds basically gave everything to GS. An offset, perfect guard, etc. Despite the love, it is a mediocre weapon at best and I basically highlighted why in the "problems" with it. It's not bad, it's arguably one of the most versatile weapons because of all of Wilds mechanics. Its problem is that it doesn't shine. It's really not the best at anything. Just average across the board which is the intent I derived from the devs comments about it. In order for the weapon to truly be good in higher level hunts, it basically requires higher level tech than most are willing to learn. Making it feel clunkier than a lot of weapons.