This was widely seen as a mistake, even by MTG's Head Designer Mark Rosewater, and since then WotC has been much more careful when printing partner commanders, instead focusing lately on cards that can only be partners with one other specific creature
Building a deck with two Inks that complement each other well and which has a clear gameplan is one of the key elements of not just this, but most, trading card games
Clearly with the rise of EDH and multiplayer formats its gotten better, and it grows at a ridiculous rate
PSA 10 price: significantly more for special or stamped versions
At least these can be opened in a booster, though it seems they are not available in foil
This isn't always as much fun for the opponents not being able to catch up with you