I was thinking the same thing, sr40ken. I don't find the factory synthetic stock flexy either.
After trying almost every Mini stock out there, factory and aftermarket, the synthetic is the best all-round stock.
It is not expensive, nor heavy, and has grippy-ness just where you need it.
The Ruger factory stock might not be stiff when compared to a McMillan stock for a single shot bolt gun, but compared to say, a Choate synthetic for the Mini, the Ruger is stiff.
You can twist the end of the Choate around like it's a Loofa sponge.
The wood stock on the Mini is my favorite for range use, where the extra weight is welcome.
You can't beat the looks of wood either.
But I try to be realistic in such matters, and although I say I vote for wood, I can think of at many reasons why the synthetic stock is superior, and all of them trump looks or nostalgia.
The synthetic is :
3) Has checkering
4) More stable in changing humidity.
5) More weatherproof in changing environments
6) Less likely to break at the wrist if you have to beat someone with it.
7) No shrinkage or compression
8) No need to ever refinish like wood.
9) Much easier to add rails on fore-end with a wood stock (room between heat shield and stock for rail nuts)
Not much out there that's as weather resistant as a stainless Mini with syn stock, except for maybe a stainless/synthetic Mini that has everything Cerakoted.