Hard agree, and I am a user with much fewer pinned tabs (i.e. sets of 3 to 6 that are always pinned across Saved Windows).
Showing inactive tabs with coloured favicons works against a minimalist UI that was once achievable in Orion.
The amount of additional visual stimuli created by showing suspended/inactive tabs in colour makes the Toolbar much more crowded than previously. Ironically the new version's solution solves some accessibility issues but causes different accessibility issues for others.
An option for greyscaling Favicons and showing them in colour on hover would be ideal.
A variation on this as a third option, preferably this would not be the only other option than the moon icon, could be to retain the new moon graphic (if this doesn't conflict with OP's request - thoughts @Whitey ?).
This could surface as a toggle in the Appearance menu: "Use greyscale for suspended tabs.".
Otherwise, a select menu for these three states: Greyscale. Icon. Greyscale and Icon.
Icon (Current State)

Greyscale without Icon

Greyscale and Icon (Colour on Hover)
