I'm not sure the Board of Supervisors can raise taxes without Disney's approval. From the FL constitution:
SECTION 9. Local taxes.—
(b) Ad valorem taxes, exclusive of taxes levied for the payment of bonds and taxes levied for periods not longer than two years when authorized by vote of the electors who are the owners of freeholds therein not wholly exempt from taxation, shall not be levied in excess of the following millages upon the assessed value of real estate and tangible personal property: for all county purposes, ten mills; for all municipal purposes, ten mills; for all school purposes, ten mills; for water management purposes for the northwest portion of the state lying west of the line between ranges two and three east, 0.05 mill; for water management purposes for the remaining portions of the state, 1.0 mill; and for all other special districts a millage authorized by law approved by vote of the electors who are owners of freeholds therein not wholly exempt from taxation. A county furnishing municipal services may, to the extent authorized by law, levy additional taxes within the limits fixed for municipal purposes.
Disney previously approved the mill rate that RCID currently collects. By writing the bill so that RCID continues, presumably this covers existing bonds as well any previously approved millage.
In addition, ad valorem taxes have to be spent within the district or on nearby transportation projects. From the bill:
Without limiting the district's authority to use ad valorem taxes and other unencumbered collected fees and revenues within the district, the district may use ad valorem taxes and other unencumbered collected fees and revenues to provide funding for public road projects, rail projects, and other regional transportation projects outside of the district's boundaries provided that such projects are within Orange County or Osceola County; improve a street, road, highway, interstate, or rail system that abuts or crosses into or through the district; serve or benefit the property owners in the district as determined by the board; and are performed, operated, governed, managed, or appropriated by the state or its agencies, Orange County, or Osceola County.
My takeaway is that ad valorem taxes collected by the district are limited to projects either within the district or nearby (mostly) roads & bridges.
Taken together, I can't imagine this gives the board a blank check to raise taxes however much they like. The money will be spent on items that directly or indirectly benefit Disney, and any increases will be approved by district landowners. Although I have read another comment, and I understand now.
Instead, as you mention:
For example, with the new board, I'm not sure the Splash Mountain to Tiana's Bayou Adventure retheming takes place because it's "woke".