I assume most uncommon PWs will be closer to Dovin and Tibalt in that they act like low power enchantments with no real cataclysmic payoff. R and MR are often bomb picks in Limited anyway even if they aren't PWs, so I don't think it will skew it too badly.
In fact I'd actually wager the real problem in Limited will be getting good creatures since contrary to an artifact or enchantment block, the PW-as-Creature or PW as proportionally effective bunch of stats through token creation design space is much smaller. Not to mention that evasion is already incredibly important in Limited but in a PW block it translates not only into being able to transcend stalled boardstates and being able to race but card advantage.