It's a one-design class - more correctly, an ISAF International Class.
That means changes are very tightly controlled to keep the boats as equal as possible. In fact, the International Sailing Federation (ISAF) must approve all changes.
When the boat was designed in the late 1960's, almost all sailboats had booms. Because the sail overhangs the trampoline by a considerable amount, the boom provides the support for the sheeting system, transferring the sheet load across the bottom of the sail. Without that, you'd need a boomlet, like what the 17 Sport has.
A Hobie 14 without a boom is not a Hobie 14. If you want a 14' Hobie without a boom, get a Wave.