[ColinWright]

  > What would be wrong with OCR plus a marker or two
  > to indicate a scannable area

Simple:

* There is no OCR that is currently sufficiently reliable

* It has no error correction ability, so is not robust against damage

* There are currently no apps I know that can perform this function

So go to it, create an app that works on all known phones and is robust against up to 30% damage, and you may have something with which to penetrate the market.

  > My biggest issue with QR codes is there is no indication
  > of what they are before scanning.

My phone tells me what it is and asks permission to open it, and the context usually tells me what it should be. I don't bother with context-less QR codes. Beside, this is not a problem with the code, it's a problem with the brain-dead manner in which some people use them.

  > That, and I dislike most forms of advertising.

I scan codes for shows, films, and shops. I know what I'm getting, and it's simple, clear, and my choice. I don't like advertising either, but sometimes I see notices of things I want to use, see, or get involved with.