You've already said that you want the 4's screen and it's weight doesn't bother you. You've already answered your question. The specs of the 4 are more future-proofed, you will need to buy a replacement Mini a lot sooner than a replacement iPad.
Screen quality and speed v. Price and more portability.
I would never go back to non-retina tablet now. I'm not young but my eyes are still pretty good, still don't need reading glasses but the clarity of the retina screens makes me think I have always been squinting slightly in the past, trying to get sharp focus on text that is fuzzy.
I would go with the full sized iPad. The honeymoon phase with my mini ended a few weeks ago and I find myself wanting a full sized iPad with retina display.
Just got an iPad 4 and i have the sames uses as you. I used to have an iPad 2 and got the new ipod touch 5th gen and was tired of the lack of resolution. iPad 4 rocks. I got the 32gb wifi version btw.