Why is defending Trucy lazy? We've literally never defended her before. In no way is defending a character who has never been on trial really "lazy". At best you can say unoriginal but even that is a streeeeeeeeeeeeetch because...again they are doing something they actually have not done before.
The general complaint of "why didn't they make a new character?" is at least closer to a real point...but it's still flawed because this series is known for reusing characters a LOOOOOOOOT. You defended Maggey Byrd 3 times, twice in the normal trilogy; a character that's super unimportant. How many times does Larry show up as a witness/part of the case? 7? (maybe more in the new game) Or the amout of Cases we get Oldbag involved? 4? And then there's Maya. Even if you want to not count the Investigations games for some odd reason, most of these Reuses are still within the Main Trilogy, especially Trials and Tribulations (often cited as everyone's favorite, can't tell if that's your own, can only presume). If you cared about originality, why did you not complain about the *actual* worst offender of this, but yet complain about this game where they are doing something new with an old character?
Or hell, if Character originality meant that much to you, why is Apollo Justice not regarded higher when it was mostly an original cast for everything? Even if that happens to be your own favorite, it's frequently said to be either the worst or 2nd worst (after JFA). The point I'm alluding to is this: what matters isn't really who's the defendant or the reuse, what matters is everything is written well/interesting.
For the "they are assuming you care without building up characterization", besides the fact that both Maya and Maggey are in the same boat here, as are a lot of normal Phoenix wright characters who they just dump into the defendant's chair, again what's wrong with injecting Trucy for potential actual growth to get attached to? If you didn't like her before, that's a thing, but if they honestly used this as a leeway to get Trucy to have more character, then what is the problem with giving her that opportunity? And you even admit that you liked her here better than before (probably because, like I said, this was used to flesh out her character). You don't have to earn any right to get on the defendant's chair, it's just given to you.
Maya being a defendant does sound boring to me, but like I said, I'd be willing to go along as long as the case was still interesting and well written.
Last thing, usually the 2nd/3rd cases are the things most people gloss over in this series anyways. Most people end up just paying most attention to the 1st/4th/5th ones cause those are the ones that are most connected. Not surprising people would complain about middle cases here.
The only thing that matters is "is the case interesting and well written", but reusing characters isn't and really has never been a factor for that. Stuff like "the villain really sucked" or "the cases location/premise was entirely contrived and reaching" would be real complaints that they didn't want to really make a new game, rather than complaining about something they've been doing since Game 1.