Good for Disney on waiting a bit longer to reopen. Depending on what happens at Universal and SeaWorld, Disney could look very smart. If Universal and SeaWorld open up with no issues then Disney can just say they needed longer to work out the logistics of reopening their much much larger property.
Cast member and guest safety should be the main factor in this decision, glad Disney seems to be taking that seriously. Their reputation is also extremely important, so slow playing this a bit is absolutely the best move. Play the long game, ensure everyone is safe, and if you lose a month of revenue to Uni, so be it.