I find it easier to not have the tanks be the one leading the raid or assault. In the groups I am in usually we have either one of the DPS or the healers be the leader, the ones guiding the whole group through battles and raids.
When learning I find that the tank tends to notice what the boss is doing, the healers tend to notice player HP mechanics like DoTs and debuffs the ranged DPS tend to notice what other players are doing. When it comes to Ops leading I agree that a tank isn't the best option as they have a giant boss in front of them and often can't see what the rest of the group is doing. If you can rely on everyone not to stuff up, tanks are in a great position to be the leaders.