which is the general idea behind controllers. They do some damage but also make the enemy's life miserable....So the group may use abilities that apply status effects rather than straight out damage.
Yes, it does feel blah when characters are hampered. But it shouldn't be the case that a character is fully effective in every single thing they do in their adventuring careers. I play a cold-based Swordmage, and it did suck when we played an entire adventure against the Frost King with numerous opponents resistant to cold. It goes with the territory of specializing, there will be times when that specialty is going to be negated. Likewise, a 3E rogue specializes in hitting vital organs and such.
Frost cheese is fun but yeah, you specialize too hard one way and it may bite you at some point but that's a lot different than nerfing an ENTIRE CLASS. My Swordmage rocked the Casbah against the Frost Giants/Titan but I'm built around multi-elemental damage. Nerfing a class by default is bad design. If you want monsters to make the PC's lives unfun then give them abilities and their own status effects.