Prior to 2013, you definitely had the makings of a bad rotation. That being said, you still had players in their prime coming off bad seasons. Lester was an ace right up until a bad 2012. Buccholz was great when he pitched, until a bad 2012. Lackey was hurt. And the fact that three underachieving guys all out in ridiculous performances makes the likelihood that it happens again really low. Let's take a quick look at how things differ...
1. Your 1 is Porcello, a kid on the rise. He's not an ace, mostly because he relies on contact pretty regularly, but with your offense, he's probably a lock to win 15 games. So even though he's not a prototypical shutdown ace, he's not a bad headliner.
2. This is where it gets messy. Your 2 is probably Wade Miley. Miley is a guy who gives up a lot of home runs. He's durable, but last yr, pitched like a 4-5. His rookie year was excellent, but he's slowly dropped off since then. He will give you innings, but his upside is pretty limited.
3. Masterson- he's had two solid seasons, a few seasons of mediocrity and the worst season of any pitcher in the AL last year. He's has injuries all over his body and his stuff declined. It's harder to return from a bad stretch when your stuff suffers (Ask CC).
4. Buccholz- see Masterson
5. Kelly- couldn't stay healthy in STL, not likely to stay healthy in Boston. Stuff is there, strikeouts are Dow, walks are up. He has the best shot to take the next step because he has such good stuff, but his mix of poor health and poor control makes me think he's ticketed to the pen in the future
So let's just say that your #1 is a contact pitcher. And how many people were saying Chien Ming Wang was an ace for us a few years back? Your number two is a durable flyball pitcher coming to Fenway. Your numbers 3 and 4 have seen injuries derail a promising career AND most importantly, their stuff has fallen back significantly. And your #5 is an injury prone wild pitcher who still has good stuff. This rotation has the upside to be okay and the downside of being the worst in the AL