[DRMacIver]

> Not only would this rob the legislature of experience,

I'm not sure it does, or at least not drastically: It robs the legislature of individual experience, but on average there's no reason you'd expect each politician to be in for the first time. They could even rerun later.

> it would also mean politicians towards the end of each term would be focused on securing their next job, rather than performing their current one.

This is a really easy problem to solve: You give a recently ousted MP a paid vacation after their term is up.

(This works better of course if you stagger elections rather than electing everyone at once, but it's fine without)