What do I want?
Warlord, more inherent Fighter utility, Warlord, revisions to several spells to make them less obtuse, Warlord, better support for tactical combat, Warlord, martial healing, Warlord, actually useful magic item pricing etc., Warlord, a complete overhaul of the CR system so that it's not near-worthless, Warlord, a rework of most of the game's feats so they don't suck so much (or, for the rare few, are not stupidly powerful), Warlord, a Cosmic sorcerer subclass, Warlord, and Warlord.
Oh, and Warlord. Might've forgotten to mention that.
What do I expect?
Mostly small tweaks, errata integrated into the rules, slight re-phrasing. Changes to the layout of the Race Ancestry chapter. Possibly putting the Artificer into the PHB. Rework of the base Ranger (the Tasha's version, with Primal Companion, will be the default; the DMG may offer a spell-less alternate version, sorta like how the current DMG has the Oathbreaker Paladin.) Book may end up 20-30 pages longer in total (unless they trim out some of the art, which is possible). People will most likely be shocked by how little changes actually change things.