No units are motorised, like they were in RTW. They have much more realistic movement speeds. Yes, heavy cavalry may struggle to catch light infantry, you need light cavalry to chase them down.

You need to know how to use cavalry in EB; I'd recommend reading Ibrahim's guide thoroughly to make sure your charges are actually working. Distance and formation matter. Furthermore, make sure you use Alt+double click so that they switch to their secondary weapon after the charge. If you charge right into the front of formed troops, the charge won't work.

Personally, I think only light lancers (Illyrian Hippeis, Curepos, Thraikian Prodromoi) and Epirote FMs are worth recruiting. Heavy cavalry are knackered after a couple of charges, and thus are much less effective. You shouldn't be leaving cavalry in melee anyway, which is the only reason to keep heavies around.

Quote Originally Posted by Titus Marcellus Scato View Post
Another factor is that most pre-CE horses were only as large as modern ponies.
That's not true at all. The Iron Age is characterised to an extent by the rise of cavalry as a battlefield force precisely because they'd bred bigger horses that could be used for more than just pulling a chariot. You also had breeds like the Nisean which were huge compared to the already big horses used by Thessalians and others.