This is for casual use without the stacking of gladiator mods on a [Deconstructor Prime]. Easily gained combo stacks with 100% additional combo using [True Punishment], and a healthy 8.5s combo duration.
No, [Blood Rush] isn't necessary. It actually ends up being overshadowed by the inclusion of the 3 gladiator mods and replacing any of the mods (besides [True Punishment]) ends up in a DPS loss. If you insist on not using [True Punishment], I'd replace it with either [Organ Shatter] or [Quickening].
And of course, no forma is necessary for this build.