Which dinosaurs? Predators usually had relatively large heads because big head > big jaw > kill better and bite off more meat. But herbivores usually did not, as they could just focus on plants (instead they could develop longer necks to reach them in various places); some species such as Stegosaurus had rather famously tiny heads.
Tiny arms are associated with Tyrannosaurus and similar large theropods, but lots of other dinosaurs had relatively large arms, such as Dromaeosauridae ("raptors"). Their arm size probably reflected how much they were used during hunting - raptors' much more so than T-rex's, the latter probably relied on its jaws primarily. Of course discussing "arms" of various gigantic four-legged sauropods is pointless...
Basically there's too much variety among dinosaurs to answer your question directly.
Can we acknowledge the super polite way the second linked article calls something bullshit?
Gregory S. Paul, in his 1988 book Predatory Dinosaurs of the World, also considered Deinonychus antirrhopus a species of Velociraptor, and so rechristened the species Velociraptor antirrhopus.[34] This taxonomic opinion has not been widely followed
Idk, I've read some relatively popularly-oriented stuff on dino paleontology and classification, and some of those areas are shockingly shaky, so I don't think this is meant to be some special "diss" at the researcher. E.g. when I was a kid I knew very well what Troodon was, it was shown in all those dino encyclopedias and "documentary" films (Discovery Channel's Dinosaur Planet), noted for having the largest brain-to-body ratio, but it turns out that the whole species was reconstructed based on vague fossil fragments (like many other species, mind you) and tenuous connections between them (i.e. without good reasons to assume they belong to the same animal), and the current consensus is that the species literally did not exist at all. Having your taxonomic reclassification rejected seems pretty negligible compared to erasing a whole damn species...