The only substantial difference I see in how this edition has affected Tau is in their Antitank options. One-shot mega weapons (Railguns, Ion Accelerators, fusion blasters, etc.) are now a full 33% less likely to one-shot vehicles. This makes things like Fusion Piranhas, Ion Riptides, and Railheads less effective in those roles.
I expect to see a lot more Ion Cannons on Hammerheads and there is actually now a real reason to take the big Pulse Cannon on a Riptide, in that it is a better anti-tank weapon on the whole (assuming you nova charge the gun, which you obviously should).
Other than that, it's more-or-less the same as 6th Edition. Minor tweaks here and there, but nothing to write home about so far as I can tell.