Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
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.
 
A fairly straightforward choice in my opinion.

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.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.