I really think it is for me. I just can't see myself buying a tablet that I will mostly use for reading, and it not having retina. Also, the iPad (4th Gen) now has as A6X. The A6 is way faster, and that really shows in certain apps. The mini may not need anything more than an A5 to push the screen, but it will show some sluggishness in some apps for sure.
I wasn't planning to get one anyway, but I definitely won't get one without retina. I'm too spoiled with my 3gen retina and do a lot of reading, it makes a huge difference for that.
I think the price is about 40-50 too high because the lack of retina. Works great for apple though because they have an easy update path for next year's ipad mini: a6 + retina.
I'm guessing the real buy right now will be discounted ipad 3's (or the not-so-new ipad).
For ebooks, after the new iPad's retina yes it's a major step down
The A5 processor and 512mb ram (probably 512mb) is also a bit if a misfire.
Worse still, Apple have with the iPad 4th gen announcement being only 6 months caused me frustration and hesitation, it makes me doubt on me as a consumer how long it will be for the inevitable mini upgrades, and to maybe just wait till spring and see if it at least gets the A6 bump too.
Knowing that the 2nd gen mini will kick the 1st gen's ass all over the place and having to worry about how soon that will happen makes it a dealbreaker. Especially at its price point.
If you can resist waiting a year, the 2nd gen will probably have retina.
Apple could have annihilated the 7" and mid-range competition if they had priced it a little better. Imagine if it was $269 or something. I'm sure Google and friends took a collective sigh of relief.