4569541 Worth a look. I would say that the world would be mostly maniraptoran, hadrosaur and ceratopsian dominated at this point. The migration of Antartica towards the South Pole has shifted the axis of Earth such that it is a much cooler and drier world than that which the original dinosaurs dominated, and those three groups (particularly the former two) found those conditions favourable. Organisms descended from their lineage would have to deal with the drier conditions and the tougher plants that came about as a result of this drying and cooling effect--something like grass would evolve and the dinosaurs would have to adapt to it. This would likely make ceratopsians and hadrosaurs with heavy beaks more numerous than those with teeth batteries because of their stronger ability to break down tough plant matter. In the Southern hemisphere, titanosaurs would probably shrink and continue to invest in armored forms, and abelisaurs would continue to dominate and eliminate the remaining carcharodontosaurs. Fleeter-foot forms would also be popular in the more savannah-heavy regions of this world. Maniraptorans would grow faster and more intelligent to catch ornithomimids and alvarezsaurids, as well as the smaller hadrosaurs of the region. Evolutionary innovation here would probably revolve around the shape of the feet, leg muscles and the arrangement of the hips and spines, as well as the brain. Birds, meanwhile, would invest in colonizing far off environments and innovating in reproduction. They would wage a war of adaptation against mammals, a war they would likely win with their enhanced diversity and adaptability out the gate. When India hit Tibet and the surrounding Middle East and later when South America hit Mexico there would be a massive arms race between terrestrial crocodiles and maniraptorans (I suspect the maniraptorans would win), abelisaurids and tyrannosaurs (probably a mix, but favouring tyrannosaurs) and titanosaurs and ceratopsians (titanosaurs most likely win, though ceratopsians would hold a number of niches the titanosaurs never touched) over the niches of their newfound continents.

Lastly, the Ice Ages. The Cenozoic's final act was less savannahs and dry seasons and more snows and deserts. This would put extreme pressure on dinosaurs around the poles, with maniraptorans really enjoying the lessened competition and diversifying alongside other cold-adapted dinosaurs (ceratopsians in particular) and some sauropods surviving via gigantothermy (much like the mammoths and ground sloths did in our own Ice Ages). Birds would also love the cold, as would mammals. I suspect mammals might diversify more during the glaciation cycles, but the fact that the ice receded relatively frequently means that they would likely not enjoy that success for long. Birds would be the real victors here, given their ability to adapt to fast-moving environments much more efficiently than mammals, and we might see birds inhabiting a variety of niches they couldn't in other territories. In the South, desertification would favour surviving tetanerine species over abelisaurids and tyrannosaurids, so if any of Neovenator's ilk survived to that long they'd enjoy success they hadn't felt in eons. Specifically, I imagine radiations from constricted ranges in South America, Africa and maybe Australia, as well as what European areas they managed to hold, if any. Failing that, I imagine that predatory terrestrial crocodiles would find success here they hadn't before. Herbivores would likely be ceratopsians, large sauropods and possibly crocodilians, for these animals are good at holding water with their massive, bulky bodies and efficient digestion and respiration systems. Tyrannosaurs, abelisaurs and hadrosaurs would find refuge in places like North Africa, Florida and South Asia, as the terror birds and ground sloths (as well as our own hominid kin) did in the mammal-dominated Ice Age.

That's just a few predictions of mine, but I'd be interested to see what more senior paleontologists who actually have PhDs like Darren Naish, Thomas Holtz, Paul Serreno and Robert Bakker might say. Hope you found it interesting either way.

This would happen in a nutshell...

my best guess is that humans never evolve and dinosaurs evolve and replace the non-existing humans as the sentient species.

If the meteor never struck, dinosaurs obviously would be rule, and over time, many new kinds would evolve. We, big cats, elephants and so on, would never have evolved since the dinosaurs would still occupy the niches modern large mammals currently have.