AGREE. i have the "7th episode curse" where i can't get passed episode 7 because it becomes dull, thats why I have watched about 150 dramas but only finished like 20 ;A; but when i do finish a drama i put it on the highest pedestal (i recommend 49 days, if u havent watched it , never a dull moment)
I recommend watching J-dramas too, however, as I have the same problem as you do but i never experience the dragging when watching j-dramas (somehow they know how to tell a story better in an engaging way even though in k-dramas there is better acting and cinematography) i recommend:
http://mydramalist.com/45-yankee-kun-to-megane-cha...
http://mydramalist.com/10-taisetsu-na-koto-wa-sube..
http://mydramalist.com/12190-gakkou-no-kaidan-2015http://mydramalist.com/32-nodame-cantabile^ all of which are never dull (all of them are cute romance but if you looking for drama at every corner, on the edge of your seat, I would start with Taisetsu na Koto wa Subete Kimi ga Oshiete Kureta)
i disagree also though, i feel like it would be more engaging if there were less episodes like 13 or 8, so the dragging out the story wouldn't occur (Hotel King was such a victim of that, such a good story!! but too many episodes...).