Its got nothing to do with being a purist of anything. Its got everything to do with 30 years of watching people devalue their firearms because they think its "cool" or "tacticool". Firearms were designed by Engineers ie: Educated people, or more blatantly put, much more educated than the hack who tried to fix it . There are formulas for mass, balance, percussion, and ballistics that I'd bet a thousand bucks that you don't have the first clue of understanding. This is the very reason why "modified" firearms don't shoot worth a crap and can rarely achieve what the original designs were meant to do, can do, and still do. The next ten owners of a "modified" rifle will be cursing themselves for buying something that some butthead attempted to fix that wasn't broken.
If its got a bad stock, then get an original replacement part. In the firearms world, plastic is a joke, and only jokers buy it.
Purist? No. Common sense? Yes, but I suspect common sense isn't so common in other people's worlds. Do what you want, The value of my firearms just gets higher.