Do you guys seriously expect cover bands to play every song true to the album? I mean, some of you sound like you would go to a led zeppelin show and chastise them for not sounding like led zeppelin.*
Part of being a cover band is arranging parts to suit your instrumentation. My old cover band was me, guitar, singer, and drums. On most songs we were short at least a guitar and on songs like sweet home alabama we would've needed about 6 more people in the band to sound like the original. I'll admit that some songs were a bit thin (Livin' on a prayer comes to mind, but the crowd sings that one for you anyway), but for the most part we pulled it off just fine.
*As an aside, there is a led zeppelin tribute band called Zoso that does sound like led zeppelin.