Microsoft is building up a huge update to Windows Phone. Dubbed Blue, the General Distribution Release 3 (GDR3), will likely land in 2014 with a notification center, improved multitasking and updated core apps in tow. According to sources Microsoft will be releasing some of the improvements meant for Blue later this year - support for larger screens (5" and 6"), 1080p resolution and quad-core chipsets (likely the Snapdragon 600 and 800 series).
So it's likely that we'll see Windows Phone 8 phablets with much improved hardware before the end of the year. Microsoft has reportedly been trying to offer speedier updates but had issues with chipset testing and bugs along the way.
Meanwhile, Redmond has also released the changelog for the upcoming WP8 GDR2 update - it will bring improved Xbox Music (easier download of music), FM Radio embedded in the Music+Videos app (select phones) and the new Data Sense aoo, which helps you regulate your phone's data usage. There's also improved HTML5 support for Internet Explorer, and the ability to set a Lens as default cameraapp. The GDR2 update will come to the Nokia Lumia lineup as a side dish to the Lumia Amber update, which will bring Smart Camera among other goodies.