On non-renewal

Pundits' Guide:

Paradis and Boshcoff are the 6th and 7th former Liberal M.P.s to be confirmed as candidates for the forthcoming election, with another 13 in the running or said to be interested. They join 2 incumbents, 2 former 2008 candidates, and 2 newcomers on their party's slate of candidates nominated so far.

So even leaving out the "running or interested" group, the Libs have nominated 3.5 has-beens for every new candidate. Which would seem to hint strongly at a lack of new blood, rather than any improvement from three elections worth of diminishing returns.