That's what we ended up doing, but it's still an unnecessary barrier. In my case, we had a workable composition, but not everybody will. What if we'd brought a Concealment Operative instead of an Assassin? My point is that some people have a set group that they roll with, and people with a T/H/D/D composition should stand a fair chance of downing any 4-man boss they come across regardless of class.
It just sets a bad precedent. What if there's a boss that requires a healing debuff to beat? Would every group be required to bring a Marauder/Sentinel? Bring the player, not the class is a solid model that lets people play what they want. I'm not asking for crazy no-healer or no-tank setups to be viable, I'm not asking for double tank/double healer groups, I just think every traditional group composition should work.
I am calling BS on ANY T/H/D/D combo remark.....this is not wow, get over it. Not every comp is going to work for every boss. If you have a friend that can't either cut it or causes you to fail a fight, replace them, suck it up, and drive on. BW does not need to dumb the game down to appease people that can't plan ahead. BW does not need to cater to people to make the game balanced around T/H/D/D.
Bad precedent would be dumbing the game down. If someone can't get a mission because they lack an ability, then they need to take it on their own to form their own group, with others that can cover said ability and win the fight. BW doesn't need to change the game because Joe, Bob, Tim, and Earl decided these were the only classes they wanted to play when they first started and they now see they came up short on certain abilities for a certain fight.