Anyone who has played Fable will recognize this feature. Arena style boss fights. Either have one circular room or have several rooms with different themes for the boss fight that takes place there. Around this room there will be iron gates with enemies behind them waiting to kill you. Wave by wave they are released, each wave gets harder than the last, possibly the arena has special mechanics like moving panels that reveal a pit of spikes for you to fall in. Then when the pit master has had enough watching you slaughter his/her minions, he/she will send out the boss of that round for you to defeat. Obviously the boss will require expertise to defeat unlike the many you've killed before it. Lastly the pit master will be the final boss. I personally would like it to be a duel boss fight for example: the Queen and her Brother. The classic boss fight in which both bosse must die together at the same time or else the other heals or revives the other to full health. Lastly this doesn't have to be a strike or raid. This could simply be reverted to a pve crucible match with endless possibilities or random stuff to defeat for as long as possible as a group or as separate teams on who can survive the longest.