I'm all for the removal of the Studio Tour provided that USH build a total of two theme parks and a resort. But you have to explain to the general public why you think removing a landmark attraction from the park is a good idea. I remember when USH announced it would consider charging people to go on the Studio Tour, it was widely criticized by theme park fans. The Studio Tour is one of the major reasons why people go to the park and is an iconic landmark attraction and given USH's limited amount of space (unless the Golf Course is purchased), I don't think we should expect something new in this decade.
I think the key factor that comes down to the subject, comes to as you said: how they approach the matter of removing the Studio Tour. Or rather...making an option to give people that, outside of the park.
USH's original identity, relied on the tour. And while it's still a large piece of what the park is, it's only a piece of the puzzle. Now you have multiple major IP's that captivate millions of people, being added or enhanced for this park, with Potter and Nintendo leading that charge. I think once the time comes on the subject of the Studio Tour's removal, that they will be transparent and blatant about what they will do to continue preserving the history of the park, while looking to expand and invest into the property, so the parks generate profits on par, or above the Studio property.
Ideally, I think the best option is to use the VIP trolleys, and do a enhanced VIP tour, that works similar to what's offered now, but goes much more in-depth on the behind the scenes and to go into buildings that they wouldn't often allow people to go into. Would it be another upcharge, like Sony/WB/Paramount? Yes. But it would keep the tradition in some shape or form.
Would also allow the studio to take Earthquake's property for a new soundstage as-well, when you think about it.