Yeh it seems your analysis cannot be flawed based on the statistics provided. However, there are a few points I'd be wary of as a Barker fan (literally). The first is that last year you could look at the stats and one could say something along the lines of the following: "Waverly came 2nd in 1st XV, and 2nd in 2nd XV with a number of year 11's returning." Also, you might have heard something along the lines of "Knox came 1st in the 2nd XV and 3rd in 1st XV, also with a considerable amount of year 11 returning, as well as a strong under 16 side" But of course the one thing you would definitely have heard was "Trinity for back-to-back, with 1st XV dominating (breaking CAS records), and practically the whole team returning where any players leaving would be replaced with their 2011 16's players who were more than capable". Yet, look where we are now. If somebody had said this time last year, "I bet Barker will win in 2012" they would be absolutely ridiculed. 4th in 1st XV, 3rd in 2nd XV, and 3rd (or tied 2nd?) in 16A's. On paper they didn't stand a chance, except the fact that they had well over half their team returning.
Leading into my second point, the funny thing is that Barkers depth is so good this year that people in the firsts last year like Clout, Naude (who played CAS 2's this year), and Lembke-Hogan (CAS 1sts 2011) are frequently playing in the 2nds (Naude was playing 2s more at the start of the season). Unfortunately there was a slight fault in the information you provided, as 10 out of 15 players are year 12 in the Barker 1st XV, and some players (like Pederson, and Marais) don't have a year 11 replacement until the 4ths. The back line will undoubtedly be strong still with Davis, Stolz, and Smerdon returning, and other 2nds standouts like Dove to replace Flaherty and Elwood-Hall a good candidate to fill the shoes of Haltmeier. but they will have difficulty finding the same strength up front with Wilson, Marais, Pearson, Pederson, Naude and Edney all leaving this year. Best of luck to them in 2013 though, and as they proved this year anything can happen in the space of 12 months!!