I do not like Nickelback.
I think they are formulaic. I think they design their songs to be just barely edgy, but not enough to be offensive. I think their motivation is less about creating music they think is good, and more about creating music they think will sell well across markets. This is what pretty much all pop musicians do, but Nickelback is trying to do it while retaining some sort of "rock musician" credibility. Of course every artist who hopes to make money needs to market to an audience in some way, and cries of "sell-out" are pretty unhelpful. To me though, Nickelback music sounds like they are trying to sell it to me. No lie, no the first few times I heard "photograph" I thought it was a beer commercial. It is 2 parts nostalgia, one part bland, catchy repetitive melody. The kind of thing that makes you want to grab a miller light and catch up with the guys. It doesn't sound like a song written about Kroeger's memories, but a song designed to let you project your memories onto is and feel them with a sense of grandness and longing. That song was written to play at graduations and reunions until the end of time, and it will.
Nickelback is the Thomas Kinkade of music. The artist/s are good at their field of art and use their skill to activate a particular set of emotions from the consumer, not to make some bold artistic statement, but to sell more. That said, lots of artists over the ages, since the rise of the middle-class anyways, have done this, and many of them are still widely regarded as good. Edgar Allen Poe comes to mind. His works were crafted to activate 'melancholy' because he said women found the feeling addictive and it was the surest way to get your books to sell. I'd say there is a reasonable overlap between people who hate Nickelback and people who love Poe, so no one has the high ground here.
The reason Nickelback music is more annoying to me than say, Justin Beiber, is because of the way it crosses genres. Beiber is pretty much limited to air time on top 40/pop stations. Nickelback has air time on top 40, adult contemporary/soft rock, county, and rock stations. This means I have to hear Nickelback fucking everywhere.