I do love these bikes, they always looks so "right".
It's a bit of a statement to say a bike should be running 30 - 35% sag. Why should it?
Don't misunderstand me, I'm not saying you're wrong, but surely different suspension designs have different characteristics built into them, all of which can be effected by the spring rate, leverage ratio, intended use, type of shock. So perhaps lapierre (having designed the thing) think 25% is correct?
Compare the Lapierre's suspension configuration with the old giant NRS (particularly chainstay pivot placement) - They're virtually identical, but the giant was designed to have 0% sag, so how can 25% be wrong?: