I think it's great that the people playing tank are willing to take control and lead the group through an instance.. but please communicate! Too many times assumptions are made that everyone is on the same page, which is a dangerous assumption.

I see adds not picked up, items not clicked, mobs not kited. There are absolutely people newer to these dungeons who will not necessarily know what is going on, even if they have seen that dungeon before.. Maybe they never have done it your way.

Save yourself 5-10 minutes of time, and spend 30 seconds clarifying.