Well, in an MMORPG I've played, they gave weaker bosses a high level heal which no player had. It made them harder to kill since you needed to outdamage the heals. They were also given the ability to teleport under certain circumstances, meaning newer, riskier techniques were required to kill them. I don't really agree with the teleporting idea, since it's annoying having to search for a boss all over again. A healing spell really didn't turn things around. It simply made it harder for less skilled players.
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In DD I felt that the amount of boss HP was rather too much...I would suggest a sort of timer on potions, since spamming potions just means you can take on anything which doesn't killed you in one or two hits (depending on attack speed).
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I agree.. I don't really like the idea either of a boss teleporting himself constantly.
As for the potions, and healing.. give the boss an inventory and mana.. does he run out of potions? ok no more potions for him.. does he run out of mana.. no more healing spells.. simple
