Having read the coresponding sections on the rulebook, I'd say they haven't changed much. The border princes got a lot more ink spilled but I argue that's due to the fact the instigating conflict in the starter sets was set within the Border Princes. A lot of names were thrown into the region, 3 imperial, 3 bretonnian, 2/1 Tilean and 2 Estalian, 1 Kislevite and 1 Norscan -- I think one of the Estalian lords was through under a bus in the Siege of Matorea scenario to explain why the Bretonnian relief force came with the Lady's Blessing (so no need to pray)
Tilea remain fractured with independent city-states, a centre of creatively, science, and art, and the first Old-Worlders to reach Cathay by land (Ricco & Rubbio) and reach the New World (Norsca not mentioned again). The city-states continue to rely on mercenaries (though the merchant princes do have personal guards, somewhat like the Rico's Republican Guards I guess). The Dogs of War can sometimes get hired to go on expeditions far from Tilea and there are Tilean outposts in "Lustria, Southlands, and the Dread Sea" (no locations given on the interactive map, though we know the Lustrian ones from existing lore). They added that the Pirates of Sartosa can get hired by merchant princes to act as Tilea's navy.
Noteably for Estalia, the lore about it consisting of many independent petty kingdoms from old WFRP 1E lore is reaffirmed. Each kingdom has their own, usually small, navy. Their military uses pike and crossbows, and their fighting style is compared to the Tileans'. They have young noble horsemen as well as Templars such as the Blazing Sun. The War of Blood against Nourgul from 5th and 6th VC army book gets a brief mention. It is also said to fight the Arabyans from time to time, and the Crusade Against Araby is also reiterated, probably to justify the Bretonnian Crusade army list. Also some Estalian nobles are of Arabyan descent.
This is definitely heftier than the 6E & 7E rulebook sections about "Other Nations", but I won't say there's any new information that hints at their coming. Note that both Kislev and Cathay gets new lore in the rulebook and Kislev has its own section of the interactive map painted while Tilea & Estalia are not, yet Kislev is not available on release