Something along these lines:
Going by levels, all types of players start at level 1, unless otherwise instructed.
Shinigami:
Shinigami can increase their power and unlock more potential by gaining levels of power.
Level 1: A new recruit to the Gotei 13. Usually placed in a numbered position inside of a squadron, determined by their combat proficiencies.
Level 2: A being that is able to unlock a small amount of power by knowing their zanpakutou's name, but cannot access Shikai.
Level 3: Able to activate Shikai at this point, the Shinigami can transform their zanpakutou to it's first form and attaining new abilities.
Level 4: An advanced form of Shikai, the full power of their first activation is achieved, giving more power and devastation.
Level 5: The unleashing of Bankai has taken place, bringing the users Zanpakutou to it's ultimate form.
Level 6: Mastery of Bankai is achieved, allowing the use of all Bankai abilities and techniques.
Vizard:
Vizards are only available until after Level 4 is achieved by a Shinigami.
Level 1: The Vizard is able to form a partial mask upon their face, increasing their power by a fair amount for one attack.
Level 2: More of a mask is formed on the face, the power bonus increasing as well as the time, lasting for two posts.
Level 3: A full mask is formed, extraordinarily increasing power, but exhausting the user after it is destroyed, or disappears after three posts.
Level 4: An extended form of the mask, being mastered only by veterans of the Vizard. Can last up to ten posts and increases power tenfold, however still exhausts the user.
Hollow:
Hollows will skip the Grand Menos stage, as it would require hundreds of Hollows and only one would survive. Instead, they would go straight to Adjuchas.
Level 1: A Hollow who has just been formed, their human bodies disappearing and replaced with a hideous creature with a white mask.
Level 2: After devouring souls and increasing power, the Hollow has become faster and stronger, able to take on tougher opponents, becoming a Gillian.
Level 3: Returning to Hueco Mundo, the Hollow begins to feast upon other Hollows to increase power and begin transformation.
Level 4: Adjuchas Menos are only capable of staying in their form by devouring other Hollows. Power, speed, and overall strength increased dramatically.
Level 5: The Adjuchas, after surviving and devouring, becomes a Vasto Lorde, the strongest type of Hollow. A massive boost to power is taken in.
Arrancar:
Arrancar are only available to Hollows level 4 or higher.
The new Arrancar is armed with a Zanpakutou, and can release it on command. This increases their strength tenfold, and gives them access to their true forms, giving new abilities.
Quincy:
Level 1: The Quincy is able to launch projectiles from a makeshift reiatsu weapon. The bolts are delicate, and only able to take out the weakest of targets.
Level 2: The weapon increases in size, giving more firepower and faster shots.
Level 3: A max power weapon is available, however it does hurt the user from the sheer force of the reiatsu.
Level 4: Only obtainable by acquiring a Quincy artifact. This creates a bow from the artifact and can fire lethal shots.
Level 5: The Quincy is able to expand their power, keeping up with very strong opponents by unleashing the artifact. This will risk death to the user.
Humans:
Level 1: A reiatsu sensitive Human will see Hollows and Shinigami, and be able to interact with the two.
Level 2: The Human unlocks their power, able to fight weak beings and stand their own.
Level 3: As their power becomes greater, they unlock more abilities and potential.
Level 4: Now able to take on Stronger opponents, humans can be a definite challenge, although they are more vulnerable than others in battle.
To level up, a person must follow their character's path In Character. This includes fighting, devouring, and discovering new powers. It takes a lot of skill and power to reach the higher levels, the process getting continually harder.
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I made this in about five minutes. It should help with a rough idea of what can be done.