All of the Power-up functions lack sufficient configuration options.

• Each Power-up should have the option to be individually enabled/disabled by the streamer. This is a bare minimum functionality.
As of this writing, the Power-Ups FAQ states that all Power-Ups are mandatory "at launch" but offers no information about when/whether that will change.

• Each Power-up should have its own cooldown settings, both channel-wide and per-user. As of this writing, the emote-spray celebration is the only power-up feature with a cooldown option. The FAQ suggests raising prices as a measure to reduce chat spam, but in reality this means pricing out some viewers from participating while other viewers with the means to afford a large volume of bits are unaffected.

• Streamers should have an option for Celebration and Gigantify (as well as any future effects that involve emotes) to restrict the pool of eligible emotes to the current channel. This is a measure to prevent abuse.

and while I wouldn't hold out hope for this one, it would be nice if individual viewers could elect not to see the effects, and instead see a chatlog description that the effect took place. It can be annoying to have chat scroll get massively inflated or to have emote spray occur during pivotal cutscenes in a game.

Additionally, despite Power-ups being conceptually similar to Channel Point effects, they should be attached to the Cheering menu instead of the Channel Points menu, simply on the grounds that they are specifically tied to using Bits.
The intent might have been to make the menus differentiate between
• "Where can I go to proc effects in this channel?"
• "Where can I go to do legally-distinct-from-tipping?"

but I believe more users perceive these menus as (more usefully)
• "What can I do with my Channel Points?"
• "What can I do with my Bits?"
and so placing Power-ups in the Channel Points menu feels like it's designed to trick viewers into spending Bits (and by extension needing to refill Bits) without realizing.