I just finished a Tarot app and had a hard time reconciling a lot of the issues mentioned here. First and foremost was trying to cater to a more or less experienced person. A lot of the apps up there emphasize a lighter, "party" or silly atmosphere that I didn't find to my taste. On the other hand, I didn't want to distance folks who were curious but inexperienced.
Pat meanings seem to be a dividing line; some folks seem to "just want to know the meaning" in one, limited way, and it's dangerous to simply present some words that they might take as a truth instead of interpretation and impression. In my app I relied on what I call "historical" interpretations -- what folks have written in the past, in this case Waite's musty old thoughts (that are, at least, in the public domain). The problem for newcomers is that Waite's impressions go on and on and--being Edwardian--aren't really accessible to a modern sensibility (at least for many).
Personalized spreads were easier (my app lets you choose classic ones, or just arrange as you wish). Experts know how they'd like things arranged, newcomers can rely on the old patterns.
The issue of touching and feeling the cards is harder. I emphasized actually moving the cards, sliding them, flipping them, choosing a different back, etc. I also let folks choose things like colors and cloth patterns to try to emphasize the tactile and personal nature of things. I figure that if you can really make something look as you'd like it, then you'll feel less of that cold glass sitting between you and the card images.
Anyway, I don't want to turn this into an ad. If anyone would like a free copy to see how I approached these issues, just get in touch (I have plenty of promo codes to give out).