upgrade worth it?
I decided to upgrade. I found a good home for my old laptop for my family members who have always had pcs. They have none stop issues with spyware and virus. Going to buy office for them and force the os to only allow them to use google chrome. They have a Ipad and Iphones as well. CC was getting a bit to slow with all my raw files after a clean install even. I have a external dell 27" I'm going to be hooking it up to as well. Maybe that is why it was running slow the res I'm running at. I don't play any games but it might be nice to play some.
Upgrading because of the GPU will not give you an advantage with LR as the current version of LR does not utilize the GPU power. Some RAW processors such as Aperture will active the dedicated GPU but Lightroom does not, it continues to use only the CPU. The SSD should be plenty fast. I have a similar set up as you, though i have a Samsung 840 non pro and a late 2011 2.2 i7, and I have no issues.
Like Tom mentioned the geek bench does show a nice increase about 40% or so. Will LR be 40% faster, I doubt it. I'm just swapping over from Aperture (though i have used LR in the past) and have yet to see my total CPU power pegged anywhere near 100%.
I agree with Tom on the SSD. The biggest difference is the jump from HD to SSD. The PCIe SSD's are faster though not the leaps and bounds jump you witness when moving from spinning HD. If you were into heavy video and/or 3d rendering then yes the upgrade is probably worth it.
LR should see a difference though I don't think it's going to be the dramatic change you are hoping for.
The biggest advantages are USB 3.0 (fast cheap external storage) and the retina display. The minor differences is the decrease in weight. I would take Tom's suggestion and look at optimizing LR.
In the end though only you can determine if the upgrade is worth it $$$ wise.