@Coookie:
You misunderstand, they are two separate points. The first being that I see Carrot’s oh so amazing jumping skill invalidated once Usopp climbed the crow’s nest right next to her, the second being that she isn’t particularly unique. Pedro might be dead but I would argue that characters like Luffy and Sanji are at least in the same ballpark as Carrot regarding jumping power.
I don’t think they have to be the best per se, but that they have to be remarkably extraordinary at it. Carrot is not and has no ambition to become that.
Again, there have been plenty of opportunities for Oda to naturally include situations where a lookout is absolutely crucial and to present them in a way where the lookout gets their own personal highlight. People may argue however often they like that such a situation might still appear in the future. The fact is that Carrot has been around for almost 200 chapters now and so far, no such thing has happened (in my opinion) even though she has been present for almost all of these chapters. It’s reminiscent of doomsday prophecies where it’s totally going to happen soon and when it didn’t time frames keep getting postponed. Didn’t some people predict that Carrot will get a lot of focus and character growth when she shares the news about Pedro’s demise with the Minks? In the end, we got absolutely none of that.
I believe that he doesn’t want to add a dedicated lookout which is why he explained in an SBS how the Straw Hats deal with it and how they already take shifts with no single person dedicated to the task. And I simply can’t see how Oda found all these different jobs for the Straw Hats and how he made them stand out in them, but couldn’t for the last person.
The doomsday comparison is funny, but I don't have such feelings for random propechies that one day there will be a great lookout moment. I don't find it likely to happen for its own sake, but rather as an eventual extention of her presence IF she joins the crew. The doomsday prophecy is in itself Carrot joining. The rest comes with the package, sooner or later.
It would be appreciated if there was already a big scene with Carrot doing amazing lookout stuff (whatever this means), and the lack of it may be a sign that it would never ever happen or that it's not in Oda's plans. On the other hand, it's cool that Carrot was deliberately featured into the role of a lookout so many times in the same arc, especially considering that the job is all about regularity and discipline, not highlights.
I understand the argument that the SHs are exceptional at what they do, but each role dictates its own ceiling of how it can be portrayed in the story. I'm hard-pressed to think how Carrot or anyone else could be better unless for superpowers like Viola's (which is borderline inconvenient for storytelling). If Carrot's jumping ability is what can set her apart from other lookouts to make her exceptional in special occasions, it's mostly speculation considering it's useful and both Carrot and Pedro were complimented for their agility to jump so high so fast. And that's how it goes a lot of the time, with the SHs being complimented for their feats regardless if others could have done (and do) the same from an abstract point of view. For example, we're considering Jimbe exceptional at helsmanship because he rode a tsunami, but the SHs had done it before pre-timeskip, so whoever was at the wheel was doing an amazing job but was never complimented for it.
Btw, if I had to imagine a great scene for a lookout in One Piece, I guess it would be something for the more adventurous tones of the series. When they're looking for Laugh Tale or scouting at the sea. In regards to attitude, Luffy also wants someone who is excited to report an island in sight (chapter 304). Anyway, I don't want to enter into fanfic territory, so I won't be writing a scene here, but I think we should go from there to think about what the ideal lookout should do and what skills should he have in such situations.