There are several discussions about unbalanced cav rushes and how to counter it, see #4941
A recurrent proposition is to remove cav from cc, which i don't like as i think allowing hunting at startup is important.
Then we can think of a new cav unit for the cc, which would be good at hunting and weak at fighting, but it would be useful only during a very short period and i think we have already quite of lot of units.
So my proposition is to increase the cost and build time of cavs at startup (by an autoresearched tech) and adds a new tech (available in corral and stables) to remove that starting penalty. That's done in that patch. The penalty chosen is a trade-off between being still acceptable for a few hunters, but too expensive for a cav rush.