My 2 cents:
This is a signing you can't help but like, because like so much of the recent activity, there is little risk involved. I liked, not loved McClellon coming out of college. I was happy to see the Bears pick him because I was afraid the Pats might bite on him. His career has played out pretty much like I figured. He isn't a bad football player, just not worth a pick in the late teens of the first round.
On the plus side, I can't help but see so much of Rob Ninkovitch in him. Ninko also came to the Pats looking not only for a job but a position. McClellon's physical talent is at least as good as Rob's, the issue with Shea is going to be can the Pats find him a position and will he blossom in it. I don't know whether it will be at DE, or LB, but it will be very interesting to watch it play out.
It is also fascinating to watch us accumulate this rash of "failed" first rounders in a year Goodell has stolen ours. It should be a good teaching point to us on how iffy even first rounders can be when you draft, and how good BB has been over the years with our first round selections, especially since 2001, most have been picked in the low 20's and 30's, with only Mayo (10) and Solder (17) as the exceptions. IIRC I read once where our average pick in the draft over the last 15 years has been 26th
The one thing we should know by experience is that playing for the Pats seems to be a rather unique experience for a lot of reasons. This makes figuring out who will fit and thrive, and who will stumble and fail very difficult. It's been pretty well documented that the Pats look for different things in their player evaluations from most teams.
Outside of the Bennett trade, all of the Pats so call first round acquisitions give us hope for this season, but they also come with equal chances of failure. Only time will determine the results on these moves. The only thing I know for certain is that they have made being a Pats fan a lot more interesting this week than it was last week.