A $700 build for what, exactly? Gaming? Video Rendering? 3D modeling? Any preferred websites? Do you have a keyboard, mouse, monitor, speakers, or operating system? Then we can start.
It looks pretty good, and I want to play new games like battlefront and witcher and stuff like that at medium-high settings with playable frames
Yeah, you'll want to stick with the i5 then. You'd probably notice pretty big fps fluctuations with an i3. You should be able to get medium-high with this GPU too, it's a pretty close match to the 960 or 770.
I like the build in the parts list above. Balanced and would not change a thing. If you wanted you could get a modular PSU and have better cable management but it is not required.