I think I share this sentiment - I'm still trying to figure out exactly how I felt about it - but I can almost forgive the inorganic nature of it because it was at least tied to Kendall's drug use, which has obviously been a thread all season. Still, I'm not a fan of Logan being saved by pure, last-minute happenstance. I generally disdain car wrecks as plot points because they always feel so lazy and random, but again, on a thematic level, it worked for the most part since it was in pursuit of something Kendall has struggled with all season, so it'd make sense that "drugs" would be his downfall.
Still, it would have been so much more interesting had Stewie and Sandy been setting up Kendall from the jump - I thought for a split second Stewie was going to blackmail Kendall with that cocaine, the way they showed Stewie pulling it out of his pocket - and I'm slightly disappointed they didn't go there.
Also, I really wish there would have been more of a nod or set up for season two. There's not even a hint of where they're going, which is kind of lame, but then again, as a new show, they didn't know if they were getting picked up when they wrote/shot it, so I understand ending the season in that manner.
All that said, overall, there a was a lot to love about the finale, and this is still one of my favorite shows of the past few years. Gonna be a long wait for season two...