Why don't you try Can you hear my Heart?

http://mydramalist.com/korean-drama/1369/can-you-hear-my-heart

Other longer drama and not draggy would be Bridal Mask.

http://mydramalist.com/korean-drama/3394/the-bride-mask

You can also try Startling with each step. Each ep is just 40 mins long.

http://mydramalist.com/chinese-drama/2969/startling-by-each-step
creating destiny I think it's really good drama with 31 episodes :))
also Shining Inheritance is great :)
Glass mask is a good one, but its currently airing. So if anyone wants to sub so it can go faster go to http://www.viki.com/channels/9657-glass-mask
uff couldnt find holy pearl with subs...well since so many ppl r recomending ojakgyo brothers...maybe ill try that one...
it's subbed everywhere O.O dramafans, dramacrazy, viki..everywhere lol
Jewel in the palace, Sea God, My precious you, Oshin, Gaksital, May Queen, Ojakgyo Brothers, The princess' man....
Those are some amazing dramas that are longer than 20 eps