It's funny, Jellico was the first to spring to my mind as well. Totally abrasive, however he got the job done in spades in the end. Frankly I'd want him on my team any day.
As for Shelby, the only time she "faltered" for me was her insistance on returning to the Borg cube to rescue Picard (before Riker gives the order to fire). This is the turning point for Riker in which he truly must stop "*****-footing" around and take command. And while the deflector beam plan didn't work, immediately firing on the Borg cube was the right call at the time.
(I remember all the talk of Stewart being written out and Riker commanding the Enterprise; that was one LONG summer!)
Of course if firing on the cube did work, it certainly would have been a different show; think of the glimpse we saw in "Parallels"... only 4 seasons long. :wacko
Come to think of it... it would have been REALLY cool if they had brought back Shelby in a cameo appearance as Riker's first officer, instead of having it be Worf for that reality.
Another thing that was always a "cool afterthought" for me: the deflector beam knocking out the Enterprise's systems meant that they wouldn't be at Wolf 359 in time for the showdown... which also happened to save them from destruction!
Kevin