Stewart had success because he wasn't scared to throw the deep ball, and that helped open things up for the offense, but it also made his accuracy stat seem sub-par. His drives would either be huge successes, or be quick 3 and outs due to higher risk/higher reward plays.
W/ Mangum I would expect a similar style offense to what Anae ran w/ Stewart, but w/ much more success on short to intermediate passing routes w/ more deep passes than Hill currently throws, and much less called QB runs.