I imagine that they prefer for their Bachelor to come from among the F3, and they do everything they can to get those guys there and give them good edits. But they also have a few back-ups just in case. Jake was a back-up; they wanted Kip or Reid but were spurned.
I am on the fence as to who is getting the F2/Future Bach edit. Roberto reminds me of Charlie from Trista's season: charming, confident (but not cocky), and hot. He seems like everything she wants, and right now she is smitten with him. Chris reminds me more of Ryan.....hunky but a little shy. At this point, he seems more smitten with her than she with him. All that talk about "butterflies" and "melting." He wears his heart on his sleeve and seems vulnerable.
I know that a few people have claimed Chris is F1. I hope they are right. But right now, he seems like a better Bach candidate, because everything points to him being ready to settle down. He is older, family-oriented and appears more invested. If she chooses freewheeling hot young Roberto over him, viewers will be clamoring for him to find true love with someone who appreciates him.
None of this is anything against Roberto. He seems like a nice guy and would be a great candidate. I just don't think he seems to need it as much.