I'm pretty sure we're all kind of right. I went over this in another post in another thread somewhere, when the news about Holden's RWD product still coming was announced.
There are a couple of principles we need to look at to determine what the product might be.
It's at least RWD.
It's probably V8.
It's RHD.
It may not be a single product in a single segment; we may see several products go to Holden.
It will not be a Cadillac.
It will not be here until post-2018.
Now it's time to go through GM's RWD platforms, now and in the future:
A1XX
O1XX
Y2XX
A2XX/O2XX (likely the beginning of VSS; less "platforms" than codified architectural solutions)
Y3XX (new Corvette)
I believe I read that Team Corvette managed a way to do F(M?)R and RMR on the same platform and we will see C7 and C8 exist TOGETHER with both models coexisting in a new product cadence, but we will only address this as a "new Corvette" as the RMR one will be first and is the only one we really "know" will be on the way in the near future anyway.
Which platforms actually will (or may) work with those principles already defined:
What is each platform reportedly capable of?
O1XX - something as small as a wider CTS to larger than an S-Class; no crossovers, RHD very questionable, coupes? convertibles?
A2XX/O2XX - something as small as an ATS to larger than an S-Class; larger crossovers, coupes, convertibles
Y3XX - RMR Corvette
What products is GM reportedly or potentially working on? What do the concepts they've done tell us about what they might be entertaining?
ATS successor (likely ATS-L sized) (2018-2020)
CTS successor (likely a little bigger, or packaged more along the lines of the Commodore) (2018-2020)
CT4, an ATS coupe and convertible successor (post-2020)
CT7, a large coupe (most likely along the lines of the Lexus LC) (post 2020?)
CT8, a car larger than CT6
Avenir, or better yet a cheaper large RWD sedan in the vein of CT6
RWD Impala successor and SS merger if there is a new Impala at all (perhaps Avenir is an exploration of this concept?)
new Corvette, RMR Cadillac twin
a product named "Chevelle"
What makes the most sense?
A2XX-based CTS successor for a RWD "Commodore" that finds its way to the US as a new Impala or "Chevelle" for more "attainable" performance like the former/current Commodore in almost facsimile
RMR Corvette as a halo product for the lineup
Now, the reach: an "Omega-based" A2XX-O2XX technicality of a Chevrolet version of a CT7 (an opportunity for scale nobody else out there has access to) to share with Holden as a Chevrolet Chevelle (effectively an Impala coupe) and a Holden Monaro (Commodore coupe) to combat the Mustang and Challenger with competitors to BOTH while offering something with greater practicality to Australia than something smaller like a Camaro or Mustang and affording Cadillac the scale to produce a business case for a large coupe that, under its own banner, will only sell as well as ELR
if they're lucky and do it right.