Best assault depends on what monster you’re facing.
For me, I’d still pick Markov when going against Goliath. Goliath is way too mobile to stay in Hyde grenades and Torvald mortars. Mines can be placed on a high point for teammate safety and lightning gun tracks Goliath’s leaps rather well.
For Kraken, Parnell or Hyde. That minigun and Shotgun are still pretty accurate at ranged and rank in that headshot damage that is Kraken’s big downside.
For Wraith, Hyde or Markov or Torvald. All three have tools to deal with Wraith’s invisibility and inhibit her movement.
For Behemoth, Parnell, Hyde or Torvald. Hyde for his grenades and Flamethrower which against immobile Behemoth deal stupid damage. Same with Torvald and his mortars, and for Parnell hitting that weakspot is soooo easy.