As a Roblox developer, it is currently difficult for some games that need StreamingEnabled due to high part count to use StreamingEnabled properly due to reliance for parts on the client-side.
For example, in a game that has 75k parts in a semi-small area (which the player is stuck in, and almost all parts are important to the design and aesthetic of the game), StreamingEnabled makes sense to enable. However, the game also has certain systems in place in which scripts rely on parts to be present and cannot easily wait for them as usual.
My proposition to fix this problem is to add a sort of filter, like the Mouse’s TargetFilter, to allow certain instances to always be replicated to the client regardless of distance, ignoring the StreamingEnabled process completely. This allows parts that the client relies on to be present always, whereas other build-related or aesthetic parts can be loaded in as the player moves.
Although the current arrangement can be worked around, this would greatly improve the development experience, as it removes some responsibility of handling StreamingEnabled replication.