Another important thing about "On Next Swing" attacks is that they are not "Normalized"... in other words, the slower your weapon, the bigger the benefit from attack power for the attacks. For 2h Weapons, AP bonuses for normalized attacks is treated as the the weapon is 3.3 speed instead of whatever it may be. Raptor Strike is not normalized, so it recieves the full benefit of your melee attack power. Basically, it takes very little AP to boost the damage of Raptor Strike in a noticable fashion if you have a very slow 2h weapon.
2H Weapons: The best weapon for a Raptor-Strike centric build is a very slow 2h. While 3.3 and slower are acceptable, the 3.8 speed of the Bloodied Arcanite Reaper and it's impressive damage range makes it the best for consistency... in addition to the stamina and crit rating. The strength helps with your mongoose and raptor strike damage but not much else. Overall a solid weapon for your raptor strikes.
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[item]890[/item] is a solid choice at 3.4 speed, and 8 top end damage behind BAR, as well as the purely beneficial Stamina and Int bonuses.
[item]1484[/item] at 3.6 Speed is better for Raptor Strike damage than the TCS, and provides the mana that BAR fails to provide... but it also lacks the stamina that TCS and BAR both can provide. The spellpower is purely a wasted staff. But still, if you want to put out comparable Raptor Strike damage to BAR while keeping a moderate amount of mana for your mana pool, Witching Stave is a decent choice.