I think there needs to be an understanding that like-for-like comparisons can be used as an input but should used sparingly. Every country and indeed every club has a unique set of cicumstances.
Italy knows it needs to change and somehow find a blend that works between tifosi culture, commercialisation and the 'gentrification' of their wider support base. Juve, Roma and Udinese have or will start seeing benefits from owning their own ground and the rest of the big clubs will all fall into line or risk being forever left behind. It's a different culture to England and their builds will reflect that.
Over here the only consistent theme from stadium builds is that attendances increase, but circumstances differ sometimes wildly. Chelsea1, Sunderland, Newcastle, Derby, Middlesbrough, Southampton all run-down shacks that needed upgrading before they fell down but all of them also knew they could significantly increase their match day crowds, some through sheer lack of capacity (Roker etc) some through abysmal facilities (Chelsea). Arsenal, Tottenham, Chelsea2 all now taking advantage of the affluence in the capital and acting accordingly. WHU and City jumped onto an athletics legacy bandwaggon otherwise both could have inconceivably stayed happy where they were and redeveloped in-situ.
One of our unique set of circumstances is that we have an extremely high sell-out rate at GP despite a quarter of a century of zero upgrades in infrastructure and facilities. The available tickets on a game-to-game basis are pretty much always solitary and are obstructed. It is without doubt that we should be increasing capacity to cater for the current and forecasted demand. Another of those unique circumstances to us is that the new stadium will be the most accessible in our history reversing the trend of the 90s when clubs moved further from their support base.
I believe we should be aiming for 60k. The challenge in terms of match day experience and intimidation lays squarely at the feet of the architect though and personally I like what he's been saying and if it means a slightly smaller capacity well let's see what we can do with it. I know loads of Newcastle fans (usually the ones who went throughout the 80s) who much prefer the 36k St James than the lop-sided 52k version.
I have faith it'll be true Evertonia.
