why has naruto shippuuden been so slow?

yeah its kinda annoying when an episode is being dragged too much. to be honest i like it more if the would just make fillers instead of stretching it. like one piece, they always have a filler after an arc but those fillers are also enjoyable

i can tell you why. you should consider the production of the anime. animation is not as easy as recording scenes through video cameras. a fifteen-minute animation already takes on several frames, and consider this, working on the frames and the in betweens are not that easy. i'm telling this based on what my animator friend had told me. so let's just be patient and understand that the production team is doing its full effort in giving us quality animations.

I have to agree that sometimes it does drag out just a little bit too much. Although fillers would be nice to have in the middle.

I think it's because they don't want to repeat their big mistake in the first Naruto series - having too many fillers. (But hey, Dragonball is the most dragging series ever! I know Naruto wouldn't be like that).