A Media Center Command would be the bare minimum requirement for me. I was VERY surprised when I found out that I couldn't set a time, rules, or conditions to load or refresh the EPG, and had to just set it up and wait for it to happen. Doing this would be just the first step to creating truly usable EPG functionality, and ensuring programs, however they are selected for recording, are in fact recorded, in full.
Add to that the ability to select programs for recording based on keywords, rules, repeats or not, priority (for when clashes occur on tuners), TV series identifiers, and no doubt a host of other things I can't list off the top of my head right now. The current ability to select a single program, or subscribe to a series, but without any control over what "series" means, is VERY basic.
There are lots of examples out there of what can be done, and what works very well. In Australia, TEDS Suite, IceTV, Big Screen EPG, for example.
Anyway, at least some work is being done on TV capabilities I guess. Thanks for that!