[Nezha] has several synergies in his base kit that can be used against almost every type of mission. We subsume a buff to help him push his damage and survivability further in various forms of content.
Elemental Ward and Warcry give you hybrid offensive/defensive options but are a bit weaker overall. Element buffs like Nourish, Smite and Shock allow you greater freedom in your weapon loadouts but may require augments or build tweaks on those weapons. Roar, Eclipse, and [Xata]'s Whisper give you the strongest damage buffs but have certain drawbacks due to balancing decisions limiting their output.
Divine Spears is usually the ability chosen to be replaced as it performs inconsistently against some enemies.
[Growing Power] benefits every ability but can be replaced with any other aura depending on the type of content you're running.
Controlled Slide is only used because this is a learner build for most players and his passive is extremely off-putting. Replace it with a regular [Power Drift] or any other exilus mod that fits into the polarity plan.
[Augur Secrets] can be swapped out with any of the other augur mods at your discretion.
Transient Fortitude can be swapped out with Blind Rage if you're confident with your energy economy.
Vitality and/or [Health Conversion] can be swapped for [Rolling Guard] or any mod that fits into the polarity plan if you're going against very high level content.
Arcane [Guardian] probably shouldn't be replaced due to the synergies it has with Warding Halo but if you're running very high level content it can be swapped out with offensive arcanes.