this seems like a great idea!!!
As a feature request for this option, can I suggest the following addition....
much appears to be improving in theatreview, tv series etc. but each new addition requires me to do work, eg. I have to select series posters manually as MC can't be too sure that I have named the show exactly the same as thetvbd (e.g. office vs office(US) etc). If in 6 months you add a feature to display banner art or season art somewhere, I am going to be doing the same thing again. When show descriptions lookup is added, I will be at it again.
So why not as part of this import option feature give me the chance to select thetvdb show id. you add a couple of additional tick boxes e.g. for this directory assign thetvdb id, or for this directory assign a imdb id or musicbrainz id for an album, etc. You take the carnac'd filename and give me a selection of best guesses. If carnac does a bad job, you give a box to type directly.
Even if you aren't using this for any purpose today, I do this ONCE now and you can then use this key to do any number of lookups of show descriptions, posters, fanart, season art, banner art, etc etc as you add more "features". These keys often work across databases also, so with the imdb id, you can get the correct movie off rottentomates, thus I am not looking up the same move 3 times to get some info from rottentomates, and thetvdb and wikipedia.
If I am adding a new episode to a directory, it may be reasonable for MC to assume if all other files in that directory have the same thetvdb_id tag, it can just be assigned the same one.
Upon new imports the action window pops up a little message saying there are some files that require some interaction, I click yes and off we go.
For me, and I suspect many others, and anyone coming from XBMC, pvd, sickbeard or similar, we have already done the work of selecting which show is which. MC is now asking me to do it all over again, and may ask me in a few weeks need me to do it again and again..... Let me give you the imdb or thetvdb id and you guys can do the rest.
Craig