Knowing ESRI, they'll keep it locked. But I haven't been up on their updates lately outside of what we get, so you could be in luck on that front. But as for upgrading, you probably don't need to much of the GPU side of things. If you're upgrading anyway, I'd say go for it so you have something fun to play with if you're into gaming. CPU is what you really want to focus on. I wasn't sure if an i5 2500k would be enough for what you're working with, but that is fairly low powered among what I've worked with, so I decided to look up some opinions and came across this absolutely fantastic comment from a GIS Consultant on reddit about all of his suggestions. As someone else said in the thread though, definitely go for an SSD if you can. That just makes things worlds better.
Saved the comment! I built my own gaming rig in 2011. At the time, Battlefield 3 just came out, and I can still run that on the max settings. It's still holding up pretty great as a gaming rig after 3.5 years. But there's a chance I might go into this, a 2-year GIS master, where you work mainly from home running GIS. Still, I love the SSD in my laptop, so I'm definitely gonna look into that.