Salut Breci,
I’m Camille, the Product Designer for Extensions. Thank you for your comment! It’s always good to see Developers passionate about design.
To address your first question, the background of component extensions is now semi-opaque, not a solid color. That is to clearly illustrate the space being used by the extension, as various studies showed that viewers were confused when overlay extensions wouldn’t work because transparent components were placed on top of them.
As a side note, component extensions will be hidden by default, which actually reduces the amount of interfaces visible over the stream. From numerous studies, viewers expressed that extensions being visible at all time and at different locations on the stream, reduced the quality of their viewing experience. Providing better control when they want to view and interact with an extension and a consistent positioning increased the ease of use.
Secondly, regarding the top bar. We wanted to standardize key extension actions like accessing setting options and closing the extension. This is a familiar pattern with any windowing system and viewers will appreciate clarity in how to control extensions in a consistent way.
About the type of extensions to build. Overlay and component extensions have different uses than panels. Video extensions are generally related or complementary to the stream content vs panels which are generally static content that can is accessible when the broadcaster is live and offline, such as social media, schedules, and so on.
Hope this helps! I’m happy to answer any additional questions you may have, here or on TwitchDev Discord.