The staff seems very useless to be honest. As currently suggested, It would be too expensive and too weak to be a viable alternative for all but the most specific niches.
I might suggest ditching the autocast spell for the staff in favor of another bonus; for example a chance to shoot two spells at once, or have a slightly faster casting speed. Another idea would be for the staff to have a DoT effect that hit about as much as super poison, but much faster, and for a much shorter duration(for example, twice as fast, for half the duration. It could even lose damage over time similar to how poison becomes weaker over time.).
I feel that these would make the staff competitive with other staffs, yet not overpower the other available options.
17-Jan-2014 19:55:57