The ending isn't bad , it's just lacking.
We never get the full party to fight , well you can see them in short cutscenes , but erf...
Cory fight is really short .
The Inquisitor makes no speech , I think you speak one line with Cory .
There's not much going on , except well kill the end boss (no loss , no choice ...)
The epilogue is great but again the Inquisitor isn't involved in it.
ME3 ending problem , imho , was purely a case of bad writing .Antagonist appearing out of nowhere , with grey choices for the sake of drama , but not making much sense with the overall theme of the games.
DAI ending lacks content , I guess it got cut .Storywise it's not great , you just defeat the big bad , but it's not terrible either.