Not sure I'd describe it as spy-in-the-cab - it only shows MCP selected parameters which are shortly going to become apparent to ATC, once the aircraft carries them out. I'm sure many crews would prefer to have the controller notice a mis-selected ALT and query it, rather than deal with a level bust and associated paperwork. I'm not type rated on anything, but that sure as hell isn't going to stop me checking with a pilot if I've cleared him to a level, and then see he's dialled in a thousand feet lower.
I do agree with you about the size of the data blocks, though; we'll see come next summer if this is going to be a major issue.