Again, if we assume that CP2077 will be released in 2015, then it must be at the same stage TW3 was last year. I personally doubt that it will be released then (I hope they push it to 2016 at least) but that's the year they said they were aiming for, so all my specualtions are based on that.
And, if you recall, with TW3 we got screenshots in February and a pre-alpha gameplay trailer at E3. In theory, they can be releasing tidbits of info/footage about CP2077 until the end of E3 (following the same PR strategy they used for TW3 when it was at the same stage of development), then focus on TW3 to build up the hype leading up to the (most likely) Q4 2014 release, while remaining relatively silent when it comes to CP2077 so it doesn't clash with TW3 marketing campaign (TW3 info was fairly scarce inbetween E3 and the end of the year). Then, in late 2014/early 2015, they can redo the same thing for CP, while working on/promoting updates/enhanced edition (hopefully it won't need an EE) for TW3.
So I'd say it's not as unlikely as it may initially sound as long as they're still targeting a 2015 release for CP2077.