I'm having the same concern. I use all 1920 x 1200 in my standard workflow. I'm concerned about the lack of a 17" model, as this screen's physical width is just about the minimum that can support two side by side pages at comfortable reading font sizes. Pixel density is high enough already that I'm not persuaded more pixels will make smaller fonts any more comfortable, and 15" simply doesn't approximate two 8.5" x 11" pages side by side no matter what the resolution is. (Put two 8.5" x 11" pages over your 17" MBP screen; note they only hang off the edge by about a half inch.)
Full screen apps with the magic pad swipe between them mitigates this somewhat for apps like Mail, Sublime Text, or Terminal, but 1440 x 900 is a poor choice for dual page word processing.
That said, after development, my second most common activity is photo triage and editing. For this, the 15" retina display could present a far truer representation of what can be expected in the final print.
But I'm concerned about the "less glare" feature. I've also always and only purchased the matte screens. They have no glare, and no false brilliance from the glossy screen. For photo editing for print work, the matte screens have always felt more accurate. I'm curious if they've gone to a single screen surface, based on glossy, but with somewhat less glare. I'm not sure I'd be interested in that.
On the plus side, a MBP 17" only fits in carry on bags that can't quite go in a commuter jet's overhead bin, while the 15" will fit easily in most any commuter jet compatible bag.
That said, the iPad 3 64GB with iPhoto and SnapSeed can ingest and edit a great deal of photos even at today's DSLR resolutions. On recent trips, I carry an iPad 3 plus a Nextodi external portable photo HDD with integrated card reader. I edit one day's worth of photos on the iPad, while archiving the full memory cards on the Nextodi.