OBSERVATION from OP: The first parts of the topic description were taken by Roblox Wiki Fandom. Please take them with a grain of salt if they are not 100% accurate.
In 2007, when Roblox was in its first stages, the platform hosted its first event called “Homestead Furniture Making Contest”, to build furniture models that could be used for new starter places (AKA templates) for any user who joined Roblox. Two users were selected and won. As a reward, they could customize their avatars. But, back then, since most things were very limited due to the technology, they chose to use “T-Shirts”. Since then, 2 years passed, and on January 14th, 2009, it was published one of the most iconic features that helped players express their avatars alongside accessories and 2D clothes, faces.
Faces use the same technique as classic clothes, being in 2D. All of them were published under the shared company account called @Roblox. The first faces ever released were “Chill”, “Check It” and “Silly Fun”, found in your inventory as you join the platform by creating your first account.
As the platform grew, more and more faces started to get published in the Avatar Marketplace (previously known as “Catalog” and “Avatar Shop”) where players could buy using the former currency “Tix” or Robux. Not only this, but they could also get from a discontinued product, “Roblox Toys”. If you were to buy a single or a pack of toys, they could come with a code to redeem and get either a Roblox bundle, accessory or a face. With its success, good things must come to an end.
With the Roblox Developer Conferences, an annual conference where Roblox employees share their expectations and upcoming features for the better of the platform, some topics were so controversial that the faces didn’t escape from being involved.
On December 2nd, 2021, a topic was published looking for feedback about how users could use faces, from 2D images to 3D heads. They provided some samples of famous faces and implemented facial animations to showcase their vision. Not only this would be implemented for 2D faces but also heads from bundles that were “underrated” for being Rthros such as “Denny” and “Junkbot”:
https://devforum.roblox.com/t/looking-for-feedback-dynamic-heads-facial-animation/1573773
This feedback topic received a lot of attention, but not many developers and users accepted this because, judging by each media, it would deform and create a distinctive look for the faces, turning the avatars more cringe and look odd. Despite every forum user disagreeing, the hateful comments turned into good insights and your official release became a reality on July 26th, 2023:
In summary, the announcement explains that players who were 13 or above with their accounts verified could turn on Voice Chat and Camera, allowing the heads to change their facial expressions based on what they are saying or doing in camera, for instance, closing one eye, make an astonished face, and so on. Although the designs were better than 2 years ago from the feedback topic, a “plot twist” occurred. When they published another dynamic head, a 2D face would go off-sale, making it rare and obligated to buy the 3D version. For example: the Chill 2D face is now off-sale and you can only buy the dynamical face for 120 Robux.
As a Roblox developer, and a player, it is currently too hard to see that most of the historical faces, being considered as “classic faces”, are off-sale. With them being “deprecated”, you don’t allow users to make their avatars fully in R6, instead, you must force them to buy heads with facial expressions that might include shapes that not many users might enjoy. This can create a scenario where not many users might use 3D heads, leading to a failure case. That said, to balance and make this more fair, they should return to being on sale with their original price (IE being free or costing 10 Robux, for example).
If Roblox is able to address this issue, it would improve my experience because I would be capable of creating a variety of avatars with different technologies to express myself in-game and show how they can be funny or even unique. Furthermore, since Roblox released a limited face called “Snowflake Eyes” in 2D for the event “Winter Spotlight”, despite thinking that it was an actual end for the classic faces, it doesn’t make sense to have this problem of having the faces off and the 3D version available. Make both of them possible to spend and use.
