I think it's fine. Different tanks have better or worse synergy with different dps. It's not always gonna be a one tank fits all type of situation. Also different combinations of tanks bring different benefits. Pld/drk for max mitigation, war/Pld for fights with more physical mitigation, war/drk for more magical mitigation. Even then it doesn't really limit or hinder your tank/dps choices. Ideally a tank would have more than one tank job leveled to adjust their playstyle to the needs of the group. Would also hope the dps have multiple options to do the same.

In the end, perfect synergy isn't an absolute necessity to complete content. It's nice to have and can make things go a bit smoother but definitely not needed with skilled players.