She would look so fucking cute with a hat

I can't wait to be a male vampire, I hope there are plenty of vampire lolis. 

Chibi art always is a good time, having it in UI elements that don't need full art is almost always a good call (Loading screens, tip screens, emoticons, etc), but I'd welcome it wherever it showed up.  I'll be the first to say "Huniepop" 1&2 actually pull off the dating side of the game really well, obviously the more modern elements would need a fantasy coat of paint if you were to take inspiration from them.  Also "PMC promiscuity" is still in development but has nailed the dialogue.  I have yet to finish it but am enjoying the simplicity of the progression.

If you want something classic and difficult, Tokimeki Memorial is as pure as it gets. You will have to micromanage everything to succeed, and a guide is recommended. You would have to use a fan translation for it right now, but it's getting an official English version this year.

A lot of dating sims have a focus on visual novel elements without much combat or anything else. Clannad is my personal favorite in this vein, and Steins;Gate is very good too.

If you want something with nsfw content, a lot of the older Japanese made VNs have something that you'd have to download a patch to see. Nekopara and The Fruit of Grisaia are two examples of this, but watch out for uncomfortable topics and themes in these, especially in Fruit of Grisaia.

Yes please on the more Chibi art of the vampiress she is soo cute!

Max Gentelman: Sexy Business and monster prom is my only real experience with Dating sim machanics but its not my fav genre. It normally have too much flavour text and make the game extremely long and boring to read through.