I always thought that Oda wanted as endgame couples Sanji/Nami and Zoro/Tashigi. Then,in the last two arcs,he managed to develop two good ships for Sanji and Zoro. Zoro and Hiyori is written perfectly and very credible as a couple,and Sanji/Pudding i think was written very well too. You have angst,you have contrast,but also sweet moments and heartbreaking moments with them. By the way,i dont think Sanji loves Pudding yet,but he could fall in love with her at the end of the series. Lets remember that we have still the mystery of the 3 eyes tribe to solve in One Piece,so i think Pudding will appear again in the story somehow.