If that's what you want from the encounter then the mooks aren't all minions.
Nonsense. At 2nd level, the 16 minions are fine. At 7th level, they are no longer fine. The minion rules break down as the PCs gain abilities that auto-damage foes.
It matters not if you have 16 minions out of 16 foes or 4 minions out of 7 foes.
Stating that the encounter design is at fault is a copout for inferior rules design. A DM should be able to throw any type of similar level foes at his party and expect the rules system to be balanced enough that the foes are not wiped out in a single round. That's the entire intent of 4E encounter design: balance that 3.5 encounter design did not have.
That doesn't mean that a given encounter won't be easier or tougher for a given set of PCs, it means that the game system does not have mechanical elements that auto-wipe out foes without a die roll. There is zero chance of a minion surviving Winter's Wrath (shy of having a specific resistance). That's bad game design and the claims that it's bad encounter design is obviously flawed due to the fact that it will work against any minion within any encounter designed by any DM.
7th level Wizard wipes out 20th level Minion with Winter's Wrath if the Minion does not have Cold Resistance 5 or higher.
WT?
How is that balanced or fun?
