I think the idea of changing the heroine's personality based on a test is fantastic
Personally I'm fine with any type of heroine, even the meek or soft ones, as long as she doesn't do anything retarded and get herself into troubles that can be avoided with a little thinking. Maybe no overly self-centered heroine too since I find them even worse than the goody-two-shoes people usually hate on. A backstory or setting that explains why the heroine's personality turns out that way would also be nice since I love well-developed and relatable heroine more than anything.
As for what I want from an otome game, it changes based on the genre.
If the game is a lightheart romance, then yes, sugary romance is a must. The romance must be well-written, with enough chemistry and development to make me feel like the hero and the heroine belongs to each other. I also prefer comedic relief scenes in my games since it will feel less tiring going through the story.
If it's a serious game, I would like the plot to be developed properly and intriguing to keep me glued to my chair. A few dark elements would also be nice, as long as they don't ruin the character for me. Romance can be secondary in this type of game.