It is the heads that have the relatively wimpy max weight loads. Getting a monopod that can handle 17 or 26 or more pounds is really no big deal. Getting a head to do more than 5.5 pounds or so is a fairly expensive upgrade.
One could always buy the flat monopod only and rotate the camera inside the tripod foot on the lens, as long as you don't switch between portrait and landscape orientation constantly.
Yes, what you said is true. Getting a better ball head is a fairly expensive upgrade. Alternatively i can get the Manfrotto 679b Aluminum Monopod and able to get a better ball head but i still prefer the carbon fibre over the aluminum monopod because of the shorter closed height, higher maximum height and lighter weight of the monopod.
I can just get the monopod only and still switch between portrait and landscape orientation easily because of the provided Canon Tripod Mount Ring for my 70-200mm but the problem arise when using the kit lens. Further on, another problem is when zooming or focusing subject which is higher than my eye-level, so i have to tilt back the whole monopod with my camera just to get that shoot.
Another plan use for that monopod is taking photos in theater event or stage drama at my Uni. Using the 70-200mm hand-held for few hours is really tiring. Last February i used my tripod but it was not very practical using in a tight spaces.