This is the same story, with every manufacturer.
I used to have a WRX in the past, I've had Hondas, and even a lifted Jeep on big tires.
Everyone complains about their manufacturer. No one builds what the 'fans' want. Get over it
If you love the current Z so much, get a '15 or '16 with low miles at some point. They are never going to turn the Z into a 450hp twin turbo anything, its highly unlikely.
At some point in the future I'd replace my Z with perhaps a newer 5.0 Mustang, used GTR, C7 corvette, etc etc, theres a big list. Part of being an enthusiast, there's always many options out there with pro's and cons.