Honestly my thought is that Sigil stacking practically the only way to create a more consistent outcome in the current game's combat. So creating a pure melee/berserker like build more viable would be nice, adding replayability to the game. (which probably will overshadow the Sigil build in terms of prowess and accessibility)
Speaking of combat, it would also be nice if multiple anatomies come from the mutant perk actually providing combat bonus or more observable effect in the future aside from very minor flavor text changes and added roleplay value.