Personally I love my iPad mini, but I suspect you should stick with the Air. In my opinion, in the end for most people it comes down to a gut level preference for one or the other. Sometime one or the other just makes you smile. At some point one needs to stop analyzing and look at how one spontaneously feels at a gut level, without worrying about rationalizing things.
So when you write about the Air, you say things like "So I was just lying in bed using my iPad Air 1 . . .and as I was using it I thought, this screen is just so nice, and I know if I got the mini I'd miss it. I love this size, and even though it may be a bit less portable, it is worth it cause this screen is great." I would tend to go with that.
This is probably muddying the waters, but I'll point out the holiday season is coming up, where there's an extended return period. So if you got one or the other then and regretted your decision, you'd have extra time to change your mind.