The same could be said about the SGX: any game made for it would just be a PCE game with more unnecessary sprites and background layers. Silly, no? Even if you didn't use the FMV abilities, every other technical spec (color palette, load times, ram, etc.) is better on the FX.
True ... but I'd argue that once you go beyond a certain point, everything else is just visual gravy and doesn't change/improve the gameplay.
Although the PCE is full of really excellent games that I love and, through clever programming tricks, simulates a credible parallax layer in various games, I'd still say that the SGX's 2nd video chip and true 2nd layer really does allow a major qualitative difference in certain game designs.
For instance ... there's the thread here talking about Stryder and it's 'sequel' Osman.
I'm not seeing anything in the Osman playthough video that shouldn't be possible on the SGX (and easy on the PC-FX) ... but I'd hate to try to do it on the PCE.
But once you've got that 2nd layer and so true foreground/background ... the differences become less significant.
Yes, the extra power is good ... but the next really useful step forward is a bitmapped layer and fast distorted blitting ... as the PC-FX's 3D chip would have allowed (if it had been included as standard), or as provided on the Saturn and PS1.
Beyond that we get into real polygonal 3D ... but I can't stand the poor 3D on the 5th-gen console machines. IMHO anyone really wanting 3D during those years was playing on a PC with a 3DFX Voodoo card!