This has been suggested in the past, but our stance on it hasn't changed: We don't want Rohan to have access to heroic infantry. We feel that it doesn't fit Rohan as its main focus is cavalry, and their infantry prowess can't be compared to other factions like Gondor, Imladris or the Dwarves.
With that being said, your points are being addressed in different ways: Spearthrowers will work as intended in 4.5, giving Rohan fantastic counters to monsters. And the Three Hunters are being added as well as a powerful melee brawler that doesn't need a King's camp.