Don't know where you're coming up with this "inherant inaccuracy" of the WSSM's. That's the exact oposite of what the cartridge was designed for. Using the same amount of powder as the STD cartridge (when talking 243) and doing so more efficiently. Giving you the extra velocity. Look at any benchrest cartridge. 6mm BR, 6mm PPC, 22PPC etc... They're all short and fat. From an accuracy standpoint, a short and fat cartridge gives you the benefit of having the burn point of the powder closer to the center. This results in a more accurate cartridge.
From Guns-N-Ammo - "It could be said the .22 PPC is the grandfather of the .223 WSSM and, for that matter, all the current crop of "short magnum" cartridges. The PPC demonstrated in competition the accuracy and efficiency of the short, fat case design. A short powder column burns more consistently, which makes for more consistent velocity and thus accuracy. Powder also burns more efficiently and produces higher velocities per grain used."
Ask anyone with a DTECH/OLY 243 wssm to show them some groups from theirs.
The only WSSM that would be necessary to "back down" on the speed is the .223. You're pushing a 55gr bullet 200fps faster than the 22-250 can. Back it down to 22-250 speeds and you'll be able to keep the barrel going before burning the throat completely out of it.
I don't have any WSSM's. Just a 300WSM Would have an upper in mine from Mike but am going try the 6mm WOA for brass availability. Have several friends with them however and all shoot incredibly well. The 243 wssm is one of the few that will make it. The WSM's are doing very well in the 270 platform. Getting 7mm Rem Mag performace from a 270. The 300 and 325 WSM's are phenominal cartridges as well.
As for the Winchester.. You can't polish a "turd" ;P Floating, glass bedding, a barrel with a huge throat and a gravel road of a barrel will not gain you anything. Disparaging a line of cartridges simply because you knew someone that had one in a platform with less than "stellar" performance in it's latter years is kind of funny.