Not entirely- Raging prevents you from casting a spell while raging, but it doesn't stop you from benefiting from something you cast *before* you rage.. which works fine with the sorts of buff spells and Swift-action boosters that are the staples of gishy combat tactics already. And the WhirlPounce Barbarian level is a standard of melee optimization that always has to be considered.
You are right on the money on the long duration buffs; but I think raging (wand whirling frenzy for that matter) would prevent some of the best swift action spells such as Whirling Blade, Wraithstrike, etc. Though I do have to agree that pounce is reason enough to strongly consider it.
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