I think we don't have enough details to make statements like this yet. Sony have shown they are willing to make esoteric gaming hardware in the past (cell architecture) and maybe they'll do something unique again this time. Or, maybe it'll just use a moderately custom model. Or, maybe it's just going to use exactly what AMD have planned for the next few year anyway (as you say). Time will tell.
I'm rooting for something unique because I haven't owned a console for 20 years and I like interesting hardware. But hopefully they've learned a lesson about developer ergonomics this time around.
I'm rooting for something unique because I haven't owned a console for 20 years and I like interesting hardware. But hopefully they've learned a lesson about developer ergonomics this time around.