the FINAL act was super rushed, basically they jammed like 50-100episodes into 25 to finish off the whole series, its still good, but they definitely couldved milked some of the stories more. spoilers, killed off hakudoshi so fast, as was kaguara, and then KIKYO. one of inuyasha new sword abilities is dragon scaled, he barely used through the final part and only specific instances, it seems like an extremely powerful ability against any demon(minus the ones he cant overpower or see like naraku hiding his aura with a magical orb.) and it can trap spirits as well.
i assume you are aware of the "spinoff" its basically sesshoramu with rin. but fans thought it was an odd series because it seems too "groomy", marrying and siring children with the person you took care of/companion through her childhood.