The Crimson Binome
Hero
The DMG has rules for turning a level 12 standard into a level 20 standard, and the math is pretty trivial. I didn't see rules for turning a minion into a standard, or vice versa.I would say there's just no question that GM who is insisting on this sort of encounter is playing 4e sub-optimally. Why not have an encounter with slightly higher level enemies? Or create some minions of the correct level (a minion of level+8 is IIRC the same XP as its standard equivalent). So if you have a level 12 encounter and a bunch of level 20 PCs, minionize the standards, and bulk it up with some level 20 standards, or a level 20 elite, or something. Now you have a more fun encounter.
The weird thing is that, it never occurred to me when I was running the game that changing the levels or grades of any of the monsters should be a thing, aside from giving a couple of extra levels to an orc in order to represent a more-experienced orc; but the idea that a level 5 solo could be re-statted as a level 10 elite or level 20 minion is something that I would consider to be quintessential of 4E, just from these message boards. Following my own definition from before, if I saw a new game which actually included rules for that, I would immediately assume that they were copying 4E.
As for why I would even want to run an encounter full of level 12 enemies against a level 20 party, it's because that's how I would traditionally show that the party is getting stronger. If you're level 12, and you struggle to beat level 12 enemies, then walking all over them when you're level 20 is a very intuitive way to demonstrate how much more powerful you are. To contrast, if you're level 12 and you struggle to beat level 12 enemies, but then you get to level 20 and you struggle to beat level 20 enemies, it still just feels like you're struggling. (One of my early disappointments with 4E was realizing that my amazing hero character basically couldn't beat a standard orc in a fight; and it felt like a hollow victory to cleave my way through two minions with one swing, since I knew that they were explicitly designed to be easy for me to kill.)
The healing surge mechanic succeeded at what it was intended to do, which was (along with encounter powers) to ensure that nobody was out for the whole day after a single fight went south; (and also to make it so that nobody was forced to play a healer, and I guess also to prevent you from abusing wands or potions).HS were just genius though as a pacing mechanism. Let the PCs go into each fight at 'full power', but ALSO be weakened. At the same time divorce healing from being a burden on one type of character, and yet don't just give it away to everyone in a way that negates resource management. Its actually HARDER to manage your HS and hit points in 4e in a tough tactical game than it is to manage the stock of CLWs, potions, and (assuming your players decide to be strategic) wands that make up 3e's single large pool of 'extra hit points'.
It does assume that you want the PCs at full power in every fight, though, which can be somewhat limiting in the way you run the game. And it also assumes that you're going to have enough encounters in a day for the limit on healing surges to be meaningful, which can also be pretty limiting. Granted, there are still an infinite number of games that you can play within those parameters, but there was a bit of a learning curve involved, and not everybody was able to (or wanted to) make the transition.