You sum things up perfectly, on why it needs to happen soon.
I'll tell you something, i only got into Erynn after i went back and stayed with her in the club>then her apartment.
My first instinct was to stay with Layla, i went out with her i'm not gonna ditch her for another girl now, even if she is my old friend(plus she's your friend only theoretically, by that point of the game you the player know Layla a lot better than Erynn).
Only going back and really paying attention (being into mysteries also helps i guess) i started to feel for this girl.
With only one save i wouldn't have paid her any mind.
To most people yeah there's very little incentive to go for her other than maybe you have a thing for blondes (her ass in that dress is also magnificent
).
Alexis was originally a one time thing probably why it kinda feels that way.
Honestly her flip from fun loving, sexually liberated(that's a compliment btw, before people say i'm calling her a whore in a fancy way) girl to "lovesick super romantic girl who loves too much" girl was a major turn off for me personally.
Good thing we have Nikki to play the fun loving, sexually liberated girl.