Useless to you, maybe, because you want to avoid headaches, but to others the 4 stats you choose create headaches of their own, as no stat is perfect or a true reflection of the whole value of a player. Is one of your 4 stats- chosen a fielding one? If not, isn't that missing a significant part of a player's true or comparative value? I don't mean to give you a headache over this, but even errors are scored by a human just like the UZR/150 observers and DRS metric nerds are doing, but in a more in-depth manner.
BA & HRs are park influenced, strength of opponent influenced and more. RBIs are largely a product or how many runners were on base or in scoring position for one guy vs another. Sometimes, those factor disparities are great. Does it give you a headache trying to make those adjustments in your head, or do you just count Ruths HRs in left-friendly Yankees Stadium exactly the same as Williams'?