That was just my opinion of course, but I base my belief on the fact that she was always forced to share the spotlight with someone else, even during her TryPokaron competitions since there were always other major characters during those that took some of Serena's screen-time away such as: Sana, Nene, Musashi, Millefeui, Amelia, Elle, or various combinations of two or more of these characters, not to mention Yashio and Monsieur Pierre's occasional appearances.
It's hard for me to imagine that this wouldn't repeat itself in some way even if she got a new special episode, because there's bound to be another character(s) who gets involved and takes up at least half of Serena's allotted screen-time. We already saw something like this happen in the Citron special where Dent decided to place himself at the forefront while Citron and Eureka were treated like extras, so excuse me for not having my hopes up too high for how Serena would be handled in a similar episode.