Sony: Arrogance, botched launch, E3 06, no worthwhile exclusives for like 10 months after launch.
Microsoft: Wants to charge for everything, overpriced accessories, unreliable hardware because they rushed to market
Nintendo: Not pushing motion controls nearly hard enough (WM+ wasn't bundled with new Wiis until the extremely recent WSR bundle), the ps2 had a better online system, overpriced older first party titles.
These are my peeves with each, I'm not sure what their overall weaknesses are.
Demon's Souls Official Thread | Currently playing: Left 4 Dead 2, LittleBigPlanet 2, Magicka