The overall story arc in DD had some good moments but it was def a weak entry. Case 2 was super bad as well and the lack of investigation gameplay elements really soured me on it.
The best thing about DD was the DLC Water Park case. That was really well done. Loved it.
It did have plenty of stuff I liked in it like Blackquill, the case 3 villain, the case 5
"taking mommy apart"
Case 5A was pretty light-hearted compared to 5B, especially with the Indiana Jones adventure in the beginning. All Case 4 did was break the flow of the story.
It's not like
case 4 happens after some huge reveal or anything. I don't think it breaks the story's flow too much. The game could have done without it or made it DLC, but I liked it, it's not too long and I didn't have to pay extra for it, so I've got no issues with it existing in the way it does. Splitting up the two "filler" cases with case 3 helped the pacing more than ruining it in my opinion.
On the DGS thing, I admit I've convinced myself that I don't /need/ it due to its mixed reception and the fact that we may never get it officially, but in the end I still want it.
Ace Attorney is one of those series where the games' perceived quality is of little importance to me when deciding if I want them or not... Because I always do. I've never really been disappointed by an AA game, and even when there's a bad case I still have fun. Plus Takumi's games have something special about them that is missing in the newer games by the different team... I adored Ghost Trick and PLvsAA and I'm sure there's a lot to love in DGS.
Not to mention that I rarely agree with these games' reception anyway. I loved PLvsAA, thought DD is one of the best in the series and I'm having a great time with AA6. If anything the mixed impressions lowered my expectations and made it easier for the game to surprise me with how good it is haha.
It being written by Takumi is a big factor in why I want it. His games just seem to have a different style to them that I usually end up enjoying more. Yamazaki games seem a little more formulaic. They have great twists and characters too but there's always stuff like an obligatory villain transformation, or an obligatory unsolved murder case from years ago. Stuff that started in Takumi games but became part of a formula when Yamazaki took over. That and it being an entire series of games means we're not really just missing out on one middling game, we're missing out on a potentially great series.