Q's quote in the episode
Death Wish, as written in the script, is:
Well, I guess that's what we get for having a woman in the captain's
seat, isn't it? You know, I was betting that Riker would get this command.
So, all it means is that Q guessed wrongly about who would have taken command of
Voyager.
Going back to the topic, I think Riker's problem, and this is the problem of all characters, both
Trek and otherwise, is that he's subject to 2 forces not subject to the laws of physics, namely
Da Plot and
Da Public.
Da Plot has him written as an ambitious young officer...except when he's not. While one could understand him not taking the
Drake (and based on the description, it was a smart move anyway. 24th-century, and the fastest this ship could go is Warp 3? Doesn't say much about the person who gets offered command of it).
However, for him to turn down the
Aries, which, while it was described as being
a relatively insignificant ship, in an obscure corner of the galaxy
when compared to the
Enterprise-D and her crew were doing, Picard also said (more importantly)
"But it will be your ship."
Further, the
Aries had detected evidence of intelligent life in the area it was exploring/patrolling, the Vega-Omicron Sector. There was the chance for First Contact, if not some other encounter. For Riker to turn this down reflects negatively on him.
And, while hindsight is 20/20, for Riker to turn down the
Excelsior-class
Melbourne doesn't look good as well. However, this is supposed to be negated by the fact that it gets destroyed at Wolf 359.