Pretty much all of the warrior abilities are instant cast, costing 1.5 seconds of GCD.
Your dps will likely be limited by the recast delays or durations, rather then the cast time of their spells.

With a click sequence, you're spamming... usually 2-5 times per second.
The castsequence will just move to each ability/spell along the way as the GCD allows.
The click sequence will work in conjunction just fine, as long as your click speed is consistent with the comma/delays.