There are currently 15 exotics in the game that can only be acquired from doing a legend or master lost sector. Not only is this outside many players skill level, but it's not even guaranteed that you'll get them anyway as they're not a certified drop. Plus, there are many other great exotic armour pieces that anyone can just get out of nowhere. Look, I have no problem with locking good gear behind something difficult, but this is a bit much. At least make it so that you don't have to do it solo, because then it would still be easier to get the armour whilst still having somewhat of a challenge.