The Nemesis bosses for each faction is a very good ideas, you can find bellow some ideas for some improvements (In my point of view of course^^) :
1/ When a player is “near” a Nemesis, the game could show a little yellow message on the screen (like for some quest or secret passages). Like that you can’t miss this cute mob!
2/ The players can make a nemesis spawn after killing an adequate number of creeps of his faction (and why not make it spawn next to the nearest boss of the campaign like the World Event in Diablo 2)
Thought about this the other day. Like, how come fighting Nemesises isnt that epic, while it is on paper? I mean entering Gutworm’s lair underleveled feels more dramatic. Adding a kind of “impending doom”-aspect to it, by maybe a sound effect or music track upon nearing a Nemesis, would for me do the trick.
Kind of interesting. Imagine you sweating, tearing and bleeding to try to best Bolvar or Loxmere Nightmage, and when you finally do - a Nemesis charging from out of the screen or the ground. Just when you finally thought you were done you get an even greater challenge. Also a bonus since you dont have to farm every possible spawn location after that. I think though that you should still be able to find it the usual way, if you havent had the luck of spawning it upon killing a boss/tough hero. Say a 5% chance to spawn it when killing a handful of different bosses/heroes.