Should I watch Pokemon XY?

Short answer: Yes

Long answer: Its one of the few series where I can arguably say that the Anime did a way better job than the games in highlighting the region while also having solid side characters/rivals that were on par with those in D&P. Heck they even made the game rivals in Tierno, Shauna and Trevor actually seem somewhat relevant. Also, if you're into the whole Shipping wars mantra, then Amourshipping is alive and well in this one(and on purpose mind you given that Paris is the "City of Love", hence the name is basically a secret love or crush that ends with an infamous final Episode with Serena). It's not exactly a series-only thing either since Serena's return Episode in Journeys is pretty significant if you analyze the symbolism in the boat scene therein.