Look for a lot of headlines with the adverb "finally."
From Mashable's "Apple finally updates iMacs with powerful performance after almost two years":
Apple's changed nothing about the iMac's iconic aluminum chassis and glass screen. Same screen sizes and resolution, same brightness and wide (P3) color gamut, and same ports (two Thunderbolt USB-C, four USB 3, SDXC, Gigabit Ethernet, and headphone jack).
Inside of sleek machines, however, is all new.
My take: March 25 is Showtime. No time for hardware.
Apple press release: iMac gets a 2x performance boost