(First comes a somewhat lengthy paragraph on 'all-stardom.' Be warned.)
The way I see it, every all-star is the 'last all-star.' Why do I say this? Logically, it would have to be that being an all-star means something different for each character. I posit that every character has the potential to be the 'last all-star' in their own right, and that they only gain this status when the property (which we may call the 'glory' of that character) that makes them such is (1.) discovered, (2.) acknowledged, and (3.) well-communicated. First, Glory must be noticed, so if it is very subtle, a very few people, who may have the perception to notice, may not have equally high talent in acknowledging or communicating it. Therefore the first key to stardom is direct, obvious manifestation of glory, such that it does not take an especially keen observer to find it. Second, glory must be recognized for what it is. Merely noticing it does no good if the observer does not know what it means to them. Therefore, glory must be relatable to many people in order for those not exceptionally possessive of the gift of interpretation to translate the noticed glory into personal impact/impressions. Third, glory must be broadcasted. No matter how well you understand the importance of a character, if you lack the communicative ability to persuade (cause to discover as worded above) another of the glory of the subject character, then it will have a limited influence beyond the personal level. Therefore, glory must (as any other type of information) be conveyed skillfully by correct choice of medium. Let us condense and recap:
1. Glory must be very discoverable.
2. Glory must be very relatable.
3. Glory must be very intelligible.
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Consider Dixie Kong: There is no sense that anything is hidden about her as a character. Everything needed to be witnessed is immediately obvious while playing the games she appears in. Contrast her with Wrinkly Kong. Wrinkly abruptly appears in a room for saving games in Donkey Kong Country II, and there is little to be witnessed of her outside of special rooms , so as of Diddy's Kong Quest, her glory has little discoverability. On the other hand, Dixie reveals much about herself in the first title she appears in (more on that comes shortly). Putting these to words falls in the realm of intelligibility.
Dixie Kong's glory is also very relatable. That she both wears pink, and stars in her own game was a beckoning to the newly arising audience, which grew from the 90's, and which has much more prominence today. In a modern world, this is very appealing to be beheld of a comparatively old game belonging to the famous Country series. The beret is a distinctive element of her clothing, further setting her apart as unique. She is energetic, as can be seen in how she plays the electric guitar at the end of each level in Diddy's Kong Quest and in her facial expressions. There could be no simpler way of conveying this idea about her than by devoting a brief condition of the game to watching her play-- clearly an effort toward display of her character. Furthermore, these outstanding elements invite the player to use their imagination, but not in such a way where it takes a significant investment of time to do so.
Finally, Dixie's glory was well-expressed. That she uniquely uses her ponytail to attack and do many other tasks, shifts from being a 'sidekick' to a main character, and has an atypical behavior and representation as a character that appeals to a select audience are all easily communicated in words, and not reliant on abstract descriptions of her existence within the franchise. Everything that may be said of her using abstract, subjective thoughts may with equal effort be spoken of using the concrete, objective, historically supported evidence provided by the immediate, on-screen portrayal she was given for the course of playing the game.
So Dixie's glory is highly discoverable, highly relatable, and highly intelligible, therefore she would, in my book, count for an all-star. The validity of saying the she is the 'last' may only be resolved after comparing her with other specific all-stars, as the above descriptions may not be applicable to them. That is, once she is established to be an all-star, every other must be measured in terms of the criteria used to label Dixie as such. If all others fail to equal or surpass her in any of these areas, Dixie would truly be the 'last all-star' with respect to herself.