Better fit, sure in theory, although every role Hall covers could be covered by someone else we already have on the roster. Better player, only if you think the world ended in 2008.
A 4 man bench is par for the course -- are we starting 10 position players for any reason?
C: Tek, Martinez (2)
1B: Youkilis (1+2=3)
IF: Pedroia, Hulett/Hall, Lowell, Beltre, Scutaro,(3+5=8)
OF: Hermida, Ellsbury, Cameron, Drew (8+4=12)
DH: Ortiz (12+1=13)
+ 12 pitchers = 25
since Ellsbury can back up CF, and so, in theory, can Drew, Hall isn't strictly necessary, and Hulett allows for the same infield flexibility we actually need Hall for.
Honestly, I'm rooting for Lowrie, not Hulett, but the fact is it could work.