We kind of fell into them, in that some members of the group put a lot of effort into optimisation whilst others can't even remember to level up their characters without being reminded. Also, we are busy people so it is rare that every player can make a session - but the group's policy is that if we have the DM and at least 2 players then we play (and the poor DM has to scale the encounters accordingly).Interesting post. The techniques you describe make sense as a way of making a game work, though personally I think I'm closer to your anathema category.
We have just completed book 1 of Way of the Wicked with only 2 players for most of the sessions. I've generally had to scale things down a bit, but the two optimised 4th / 5th level characters have almost been holding their own against 6th and 7th level NPCs. It will be interesting to see how it goes at higher levels - higher level published adventures as written have been a cakewalk up until now but I've got a feeling this time the writers might be able to cope iwth my players. (If not, the next campaign is going to be Slumbering Tsar; that should teach them a lesson!)