I agree to a certain extend. They have too much health and it takes too long to kill. However I must say when I play wow there are raidbosses that take the same amount of time and I have to shoot frostbolts instead of bullets. In that extend I don't see what your problem is. But I do agree that it's clearly more boring to focus your gunfire for 20 minutes, squeezing your eyes and keep pushing the trigger button for 20 minutes as it is much more exhausting than pressing 1 for 20 minutes without looking. My biggest question about this is why do Strikes? If an average match in Crucible takes around 20 minutes and 1 boss takes about 20 minutes. Isn't it better to just do Crucible matches? I really want to know because I love to kill bosses but yesterday after 30 minute fight with the Archon priest we died on him having around 20% health. The succesrate is a little bit better in crucible and less exhausting.