err... you mean like Kalarel in KotS? You can use higher level monsters in an encounter as long as you follow the point buy guideline to make an appropriate encounter level.
While many people praise Goodman Games adventures they often have very Grindy high level elite and solo creatures as well...
Yeah, you
can use higher level monsters against PCs, I just don't think you
should.
As you say, the high proportion of higher level elites and solos are the number one reason that contributes towards the grind. I find that is a really lazy way to approach adventure writing. An approach I can easily do myself. I find 4th edition works best when the PCs are outnumbered, even by lower level foes. Elites and Solos (especially higher level ones) actively work against that.
Instead of looking for creative ways to make an encounter harder, the easy way is to stick a high level elite in there. I can do that myself. If I am paying for something, I want it to be substantially better than what I can produce myself. I want it to have cool, evocative fights with plenty of terrain to interact with and a wide range of opponents. I want every battle to be meaningful, avoid stagnating and grind, and advance the plot.
My ideal dungeon would have 2 - 3 encounters (Party level to Party Level +2 or 3), a skill challenge or two and a then the big, dymanic, edge of the seat, pull out all the stops boss battle where the PCs are outnumbered 2-1 (Party level +4 or even 5). Wrap up the whole adventure in a session, then come back next week and deal with the plot hooks the PCs want to follow up and run the next, evocative, interesting adventure.
Do I want I lot? You bet I do! I have high expectations for my gaming dollar these days. If it's not better than I can do in a few minutes with a conversion of one of my (many) 3.5 APs then I'm not really interested sorry.
But give me something that takes my game to another level with a minimum of prep and effort from me, and I will be all over it like white on rice.
