My first homebrew: fixing the ragechemist

Hi Pathfinders! As title suggests, i tried to fix the ragechemist as it's a bit underwhelming albeit with a fantastic idea! Here you are, let me know what you think!

Ragechemist (Alchemist Archetype)

Some alchemists seek to perfect the body through careful experimentation, while others seek to unlock the primal power hidden within the flesh. Ragechemists are those who attempt to chemically induce a state of unparalleled physical violence, creating a volatile mutagen that transforms the calm scientist into a raging monster.

Raging Mutagen (Ex)

At 1st level, a ragechemist alters his mutagen into a powerful combat stimulant that induces a chemically controlled rage.

When a ragechemist drinks his mutagen, he gains the benefits and penalties of a barbarian's rage, treating his alchemist level as his barbarian level for determining the bonuses granted by rage. This replaces the normal effects of the mutagen.

While under the effects of a raging mutagen, the ragechemist cannot use extracts, spell completion items, or any other ability that requires concentration or careful manipulation. He can still use bombs and other alchemist class features that do not require such focus.

A raging mutagen lasts for the normal duration of a mutagen. The ragechemist cannot voluntarily end this rage before the mutagen's duration expires.

This ability replaces mutagen.

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Totemic Fury (Ex)

At 6th level, the ragechemist's experiments begin to awaken a specific form of primal power within his altered body. He gains a lesser totem rage power from the barbarian rage powers list for which he qualifies.

At 10th level, he gains the corresponding totem rage power.

At 14th level, he gains the corresponding greater totem rage power.

The ragechemist must meet all prerequisites for these rage powers. These rage powers function as normal barbarian rage powers, except that they apply only while the ragechemist is under the effects of his raging mutagen.

These abilities replace the discoveries gained at 6th, 10th, and 14th levels.

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Greater Raging Mutagen (Ex)

At 11th level, the ragechemist's formulas have pushed his body beyond normal limits. Whenever he uses his raging mutagen, he gains the benefits of greater rage, as a barbarian of 11th level.

This ability replaces greater mutagen.

A ragechemist cannot select the greater mutagen discovery.

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Blood Rage (Ex)

At 2nd level, a ragechemist adds blood rage to his formula book as a 2nd-level alchemist extract.

This extract functions as normal, except that it is considered part of the ragechemist's own research into chemically induced fury.

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Mighty Raging Mutagen (Ex)

At 18th level, the ragechemist achieves the ultimate expression of his experiments, allowing his body to enter a state of terrifying chemical fury.

Whenever he uses his raging mutagen, he gains the benefits of mighty rage, as a barbarian of 18th level.

This ability replaces grand mutagen.

A ragechemist cannot select the grand mutagen discovery.