Honestly a lot of people think that when Blizzard says "shorter expansions", they mean a year long expansion and a new one instantly after that. Not to mention the whole discourse about paying for glorified patches.
But what they're actually talking about is the long drought that follows the end of an expansion, which usually lasts almost a year by itself. That's still part of an expansion, and that's the thing they want to shorten.
Even now, we're in the drought period. The last proper patch came out and now we're just waiting for the TWW pre-patch. If TWW comes out this summer I say they've achieved the shorter expansion thing they want to do. If we're getting a patch every 2 months, a 4 month period between the end of an expansion and the start of a new one doesn't seem too long.