I disagree with the OP. Standard saves for everyone, that is the idea of standard saves.
In earlier editions of D&D minions were just lower level monsters. They had some problems though.
- They couldn't hurt the PCs and so weren't a threat
- They died immediately to area attacks regardless of whether they succeeded or failed on saving throws due to low hp values
- they required about the same book-keeping as other monsters, having hp, saves and damage dice.
4e minions are a small but credible threat. They have lower book-keeping than standard monsters. They don't die immediately from splash damage or auto damage - 4e damage values are lower than in 3e and fights take longer so autokills would look strange.
Depending on the campaign style, I think it will be often obvious some monsters are minions - groups of guards, soldiers, ninjas, stormtroopers etc - the faceless footsoldiers of the enemy. This may create a natural progression of using at-will abilities to hack through the faceless minions, encounter powers to deal with the tougher henchman, and keep the bulk of the dailys for the face off with the solo BBEG and surviving minions.
Yes, there will be an amount of frustration from those who "waste" encounter or daily powers on minions, especially when the DM concerned insists on *always* concealing a creature is a minion. But the flow of power use in a particular campaign will be an individual thing that will take time to get a feel for.