If you like the idea of handing out buffs to your teammates (and it sounds like you like the look of weapons already), go for AST. It's much closer in playstyle to WHM than SCH is too.

SCH is a very technical job, and you have to be precise with it. If you, for example, mistime Indom, it's on CD and you can't just cast it again, not to mention things like ET which modify the next spell, instead of simply casting it with one button like WHM and AST. TBH I haven't felt that managing the fairy is that bad, but a lot of SCH, for example, don't place the fairy which makes me cringe (and means the fairy loses out on a lot of healing due to following you around as you dodge). It's not hard to do though...

From your own descriptions it sounds like you would like AST more. But, you know, this is Final Fantasy... you can try both at your leisure.