So I loved Cruel Romance. I also loved Black Devil and the White Prince, Scarlet Hearts - Moon Lovers and NovoLand - Castle in the Sky. In essence I like dramas with:-

- Bad, Antihero Heroes - Maybe they are gangsters, villains, or delinquents but they soften up towards the heroine lead and fall in love with her. I like the hero crazy possessive and obsessive towards the heroine like in Cruel Romance. Dominant and demanding, but also gentle and needy. He has to be loyal and only have feelings for the lead female (no cheating or affairs). Maybe he even goes to extreme lengths to keep the heroine for himself and wont let anyone else near her. 

- Fantasy/Supernatural/Sci Fi are my favorite genres of romance dramas, but other types I enjoy too. So recommend anything!

- Intense, steamy scenes between the heroine and hero. It may be gentle signs of affection and kissing, or it may be the notorious 'wrist grabbing' or 'pinning against the wall and kissing' kinda scenes. I would like the drama to mainly consist of romance scenes and developing of the characters feelings - action and plot come second to that as the romance is the main important focus of the show. 

- Shy, timid or average heroines are my favorite (like in black devil and the white prince) where she grows as a person throughout the show. But courageous and funny heroines are also likable. 

- Long shows are preferred or movies - So newer shows with only a few episodes I may pass on as I hate having to wait for updates lol (>_< I'm not very patient). Also, fast paced shows are better than slow ones - I get impatient when it takes 15 episodes for the leads to start showing romantic interest to each other. 

I know this is a lot of requirements, I don't expect for others to recommend shows with all of these included, but the more the merrier. I'm sure there are lots of others out there who like these types of tropes in dramas/movies. Let me know what you'd think would be ideal. 

Some shows I can recommend myself for others reading this discussion is : - Scarlet Heart... Faith... Goblin... Kill me, Heal Me... You're Beautiful... The Fox in the Screen...

Share your favorites and recommendations!! :-)

Hana yori dango (is a must watch)
Summer's desire
High end crush
Falling for innocence
Cheap love
Leh Ratree- it says it is 12 episodes, but they are 90minutes each so it is longer.

Pin Anong- the guy is basically what you are looking for, but the main girl is so innocent she gets annoying.

Secret is a must:

and, I recommend you drop everything and watch it right now. 
Love me if you dare! Highly recommended
Too Late to Say I Love You --- Intense, Possessive Obsessed Anti-Hero, Gentle yet strong Heroine, plenty of Passionate Intimate scenes, a weird element of supernatural towards the end.
Sound of the Desert --- Intense, Possessive Obsessed Anti-hero and Hero, female is gentle yet clever and feisty, Passionate Intimate scenes .... Wuxia elements.
Tree of Heaven --- Intense, Possessive Anti-Hero, gentle heroine, passionate scenes.

Summer's Desire --- Intense, 2 Anti-hero/hero , Obsessed, Possessive, jealous, angsty love triangle, lots of very passionate scenes.
Meteor Garden ---  Intense, Obsessed Anti-hero changed w/ her love, possessive, jealous, passionate, excellent director, good writing, bromance.
Lady & Liar --- Similar to Cruel Romance .... I feel the writing and characters  are weak, despite the good plot.

Very Intense, bit obsessive, but low on jealousy:
The Princess' Man --- Intense, Hero then Anti-hero, female is gentle yet clever and strong, passionate love...excellent

this one has some very dark theme, obsession, vengeance, blackmail and jealousy, the male lead pretty must forces the female lead to be his sex doll/mistress, so he can torment her, but deeep down he loves her but he abused her so much is hard to watch.
Another Oh Hae Young. Go for the kiss scenes hahahaha
Wow thanks for the suggestions. Lol!! Will watch secret next, its on my list of shows "to watch". Lots of interesting dramas here, I will check them out. I remember sealed with a kiss, was very dark and intense to the point of being unwatchable lol but it was good!! Thanks all. Keep em coming
I need romance looks interesting. Cant wait to watch that
The one that pops in my mind that is almost everything you ask accept the whole anti hero is Eternal love. 
Heartles city - ticks almost all criteria: antihero gangster, average female lead, super steamy BED scene. This one is a 16 episode noir genre korean drama.

also maybe try:
the Devil
love me if you dare
new tales of a gisaeng
nine times travel