The problem with "Instant OFF GCD" abilities makes combat feel less rewarding.

[Kanzer]

Do it all the time on my 34 PLD. It's called weaving, you should give it a shot.

Fast Blade > weave in Rampart (or Bulwark if you prefer, makes no difference) > Savage blade > Weave in Fight or Flight > Rage of Halone > Weave in Blood bath.

I have them all up in a single combo and didn't miss a beat.

It's not difficult. It doesn't even have to be in that order!

And if tanking multiple mobs, you can even tab between them and hit them with the different abilities to build threat more equally while weaving. Maybe even throw in a flash every now and then.