Nah, the channel time is the biggest drawback. While you're channeling Rapid Strikes, you are unable to block damage. I could simply just block cast my spammable and negate 60% of your dmg while doing 100% back to you. Worse yet, it has no snare, meaning I could run fast enough to stop you mid channel. You could make the tooltip 18k and I would still choose an instant cast spammable with a 13k tooltip.