Absolutely!

I performed many, many searches looking for possible reward seats on different itineraries, and the option of Star Alliance Rewards appearing in addition to the Aeroplan Classic and Avenue rewards seemed entirely random (and infrequent! )

I am looking for a holiday for my family (5 of us), so the call centre fee suddenly becomes quite large. It is annoying that they charge per passenger, rather than per call that results in a booking.

From the answers so far, it appears that the consensus is that most of you call in rather than trust the limited options presented online.

If the purpose of this is to raise more revenue by having frequent flyers call in, why doesn't Aeroplan make it clear on the website that only limited options are presented, and that Star Alliance flights are unlikely to appear, especially if there is availability on Air Canada. That would save a lot of frustration for the airline's "best" customers.