Adaptation/Variant: Mysterious Sorcerer. Good idea or bad?

[Xuldarinar]

An idea for an adaptation came to me not long ago so I thought I would share, see if people thought it would be good or not. I'd put this under homebrew but such a simple variant I thought I'd throw it here and see what people think. Would this be better than the shadowcaster? Does this fix its problems? How would you go about optimizing this?

SORCERER VARIANT: MYSTERIOUS SORCERER


Class Features
The mysterious sorcerer has all the standard sorcerer class features, except as noted below.
Mysteries: A mysterious sorcerer casts mysteries instead of spells. Ignore their spells per day table, but follow their spells known table for the purpose of how many mysteries they know of each given level. As shadowcasters they may learn mysteries more than once. Unlike shadowcasters, they cast entirely from Charisma and gain additional uses of mysteries based on a high Charisma score. These additional uses are floating, unlike the rest of their uses which are keyed to each individual mystery. Unlike a shadowcaster's mysteries, these do not inherently advance to spell-like abilities or supernatural abilities with level.
Caster of Shadows: A mysterious sorcerer does not inherently acquire a familiar. A mysterious sorcerer may treat all levels in mysterious sorcerer as levels in shadowcaster strictly for the purpose of qualifying for feats.

[jedipilot24]

Put this in Homebrew.

[Xuldarinar]

Put this in Homebrew.

"I'd put this under homebrew but such a simple variant I thought I'd throw it here and see what people think."

Presenting from the notion of "If I do this, would it help fix this". Would it be more acceptable if I phrased it more as 'Would a sorcerer with mysteries in place of spells be a suitable substitute for, or even be superior to, a shadowcaster?' This falls under the altering of spell lists described in the DMG anyways.

Edit: I'll include this as part of a homebrew project of sorcerer variants then.