Brewmaster (Tier 1 in 7.2 to Tier 1.5 in 7.2.5): Slight nerfs and QoL changes (that end up being slight nerfs as well). Makes the class less fire and forget on it's active mitigation. Brewmaster will always be viable on fights with mobility/cheese. Overall goes from Tier 1 to Tier 1.5 with the changes.
Guardian (Tier S in 7.2 to Tier 1 in 7.2.5): MoU nerf makes us less adept at constant magic damage (Krosus), but ToS doesn't have a ton of those fights. Burst magic damage isn't a problem due to Bear's having the strongest defensive CDs. Ironfur nerf means we're probably behind Warriors on pure physical damage fights (if all the damage is blockable, if it's burst physical that isn't blockable Guardian is still stronger). Guardians high HP and CD tookit will always make them a viable tank for progression. Overall goes from S Tier to Tier 1 on progression.
Protection Paladin (Tier 1.5 in 7.2 to Tier 1 in 7.2.5): Minimal changes. Paladins have always been strong, but outside of Shield of the Righteous are very squishy. More gear = more haste = more SoTR uptime, which always makes Paladins good. Requires good/exceptional play on progression. Overall goes from Tier 1.5 to Tier 1 (just from other classes nerfs).
Protection Warrior (Tier 2 in 7.2 to Tier 2 in 7.2.5): Minimal changes. Great on fights with physical (blockable) damage, but will always struggle with magic (burst or sustain) and non-blockable physical damage. Overall stays at Tier 2
Death Knight (Tier 2.5 in 7.2 to Tier ? between 1-2): Tons of changes and I don't play one to comment on the viability. Some Dks are putting them at Tier 1 status, but they'll probably be anywhere from Tier 2 to Tier 1.
Vengeance DH (Tier 3 in 7.2 to Tier 3 in 7.2.5): Decent amount of changes, but most are focused on damage. Demon Hunters struggle with a bad toolkit for progression fights. And they're not overpowered/broken in any way, which puts them around Tier 2-3.