I really don't see how the characters being 'playersexual' is detracting whatsoever from their character and somehow not making them unique. It's nice having your pick of the pie and not having to settle for the (usually poorly written or unappealing) shoehorned gay romance like it was in the past.
People personnality is defined by their choice. If for all of them, their ideal partner is basically you, whatever your gender/race/class/background, and the only condition is getting along with you, this means that they basically all have the same outlook on a partner (except personnality) . In real life, people will choose you based on differents things, ranging from appearance to personnality,gender, job, age, social situation and what not.
Also, and this is another topic, While Ed greenwood stated that bisexuality was the norm in forgotten realm, I have yet to read that. because in all the Greenwood and Salvatore book I read, heros were almost universally straight, Elminster, Drizz't, Wulfgar, Artemis, and what not. And while some hero like Elminster have spent time transformed as the other gender and having straight sex from the other side. its not the same as ''being pansexual and having sex with whatever gender and race in Faerune''. Also, its seems that this tendancy is more shared by immortal divinity bored of their usual fun, and has become more regular since the 5th edition.
Please note that I'm not against a pansexual character. I could imagine a very curious, open minded and adaptable character that would like to experiment whatever he could. But all of them, I dunno, it feels so different of what I know of forgotten realm and how real life is.