Well, each fills a specific segment--subcompact, compact, midsize, fullsize, speciality. The first 4 segments (as FWD models) is the standard approach taken by most full-line mainstream automakers...Ford, Hyundai, Kia, Toyota, and Nissan do it (and VW outside NA).
GM is kind of moving things around with the new models so keep expecting changes is size. Don't forget the RWD Sports Sedan still to come too.
I think in time the Malibu and Cruze may be folded into one model. The Chevy fleet is getting crowded with all these sedans Sonic, Cruze, Malibu, Impala and Sports sedan. I could see two merging to one in the next gen. All of them will get smaller over time and there is only so much room.
Yes for now but as the 54.5 CAFE comes I see them all shrinking unless they find that missing silver bullet. At some point I see some models from many companies may be phased out as they will be too crowded.
As for your SS... It is coming and you will be glad it was not an Impala. It will be of SS power not ZL1.
Edited by hyperv6, 04 April 2012 - 04:07 PM.