I'd imagine in a salary capped sport, it's almost impossible that one man has total control over recruitment.
I'd reckon it would have to be the case of the coach & director of Rugby being in very close discussion - Coach tells DofR what type of style he's looking to play, gives a long list of players he'd like in order to play that style and then DofR goes off and plays fantasy football, compiling a squad from the coach's list, while keeping within confines of the cap.
No disrespect to the individuals concerned, but I'm 99.9% sure that the likes of Russell or Minikin wouldn't have been anywhere near the top of Powell's wanted list - They merely fitted within the salary cap.
If you look throughout SL, most squads are padded out with very average players, so ultimately its quite difficult to pin any problems on one person - you could nail the coach for not making the most of his squad, but can also blame the DofR for not signing the right players from the list, and also the club in general for not finding the best youngsters to feed the first team from the academy.