Raven "makes it past Rachel" because Nick wanted Vanessa; it didn't matter to him who was F2 or F3. So he made Rachel F3 b/c production wanted her for Bachelorette.
Why? Because: A) she's *great* & very well-liked among production/the other girls; and B) they've been under pressure to produce the first Bachelorette "of color" & Rachel has everything they could hope to find.
FYI: Once "The Bachelorette" found its groove, the selection of the next season's lead started following a very predictable pattern: Virtually always F3; *maybe* F4 in a pinch. F2 is almost never chosen b/c the PTB think it'll look bad if the girl--who is supposedly still "devastated" by her painful (and JUST-aired!) rejection--then turns on a dime & is ready to start "finding love" with 25 new men just 2 weeks later!
Jojo was the rare exception to this rule, btw. (Probably b/c Caila was so BLAH & b/c Jojo was killing it social media numbers.) This also explains why she took it SO easy on Ben on ATFR re: the "I love you" stuff! If she'd seemed too hung up on it/him, it might've seemed like she wasn't "really" ready to find love again so soon! (All such laughable B.S.)
Disclaimer: I am NOT saying that Rachel *will* be the next Bachelorette, just that they're angling for it. That decision can change up til the very last minute. Plus there's a decent chance that Rachel will actually turn down the offer. We'll see!