Create a Drama Calendar

This is good, but if an episode is canceled that week we have to update it, so we need that function too. Dramas should show in the list based on the airing date on the episode guide.

Also, you would need the function to update it if a drama's air date gets pushed back, extended, or shortened (as has been the case recently with under performing kdramas).

can't we all be responsible for the calendar ? updating it as a community 

Yeah @ArabianBeauty, that's genius !

The way I find out what is playing ( for Korean dramas) is going to this site: http://www.koreandrama.org/whats-showing-now/
It is in order by the station airing it, rather than by day. If I am looking for a Monday Tuesday drama, I still have to search the entire list, which is not ideal.
A Calendar would be wonderful. It might be a bit overwhelming to have a calendar of every drama, from every country, airing on every website etc... Something like this may be better to be suggested to the stations that play them (if you are lucky enough to have a station playing locally), or by the Viki, Dramafever, etc.... 
In fact, I may go directly to those sites and suggest it. 
As far as organizing the dramas you are interested in, I recently requested an extra column in the Currently Watching section for day of the week it plays and to be able to reorganize the list based on that. Perhaps it would be good to add that column to the Plan to watch section as well. 

I use an app called TV Series to keep up with my shows (Asian and everything else too)! It's awesome, you should try it!

MALhas a good calendar, it's pretty much a database of all anime ever aired, but it has the season, date, day and standard airing time of each episode registered. Also, it's fine to have all dramas on one calendar, that's why we have filters (as well as the filters currently in the search like country and genre we could have filters for personal watchlists as well, like CW and PTW, etc) -  there are a lot of shows, granted, but it's not like there is an overwhelming number of dramas airing at any one time.
On MAL there's also a status tag to note if it's on your watchlist, and how many episodes you've watched, as well as a bunch of other info, without having to open the page - it's really detailed and useful, and it's good to see shows you might miss otherwise - especially films.
This feature would be really awesome! I always forget which days episodes are released, and it's a pain having to hunt through all the listings page by page ><

(Also, open group management would probably be a bit of a mess, but an algorithm could be set up to automatically list shows in the schedule as they're added to the database, that could then be altered by admins manually if necessary as mentioned previously. All the data is already listed, as the shows are registered with dates and standard airing times and even episode lengths already, so it just needs to be brought together into one place. Of course I'm no coder, so I have no idea how simple or complex an issue creating this is, but it would be much appreciated! ^^" Saranghabnida!)