Knocking the stadium down to rebuild seems wrong to me. Re-developing is much more in keeping with what's happened to it over the years.
I don't know exactly what leads people to call it a "shithole"? When the weather is grim, as it was at a few games recently, people get wet in the bottom of the 1st tier. I'm sure I've felt the rain when the wind has been vicious in my seat in middle of 1st tier Stretford End. But aside from that? I went to the old wembley and even as a kid was astonished at how ramshackle that was, OT is nowhere near that level. Plus, in terms of modern stadiums, the new Wembley is shiny but pretty soulless and definitely not fit for purpose. I still get flashbacks to the rivers of piss at HT at one final. Maybe it didn't occur to the designers that vast numbers of fans would want a drink and then a piss in a short period at HT? Clearly not. So you end up with a crap stadium, it's just that it cost £££ and is more shiny. The pragmatic option is surely to renovate.
Even if you agree with a complete demolition/rebuild, do you have faith that can be done well? Which is a big caveat on that option, surely? That option is surely "I think the stadium is currently not fit for purpose, but I reckon a stadium I've never seen designed and built completely out of my control will be loads better"!
Plus, the club shelled out loads of cash a few seasons back to make the stadium better for disabled access, making changes to both ends. They've invested, albeit not enough, but come on, the stadium isn't currently too bad? Maybe I'm spoilt? W203 is fine. I'm happy to hear about other bits that aren't? MInd you, one area that has affected me (& others ) is their refusal/unwillingness to fix the platform at the ground. Train access stopped in about 2017 and has never resumed.