Twitch Enhanced Broadcasting is by default a downgrade compared to server-sided transcoding.

1. Server-sided transcodes provide a 3500kbps bitrate for the 720p60 non-source track. When using Twitch Enhanced Broadcasting, the 720p60 track is limited to 2500kbps, a reduction of 1000kbps or approximately 28.6%.

2. Non-partners are effectively denied from streaming 720p60 at 6000kbps. As twitch reduces transcode availability, more non-partners will be forced to use Twitch Enhanced broadcasting to have multiple encodes. Twitch Enhanced Broadcasting limits the bitrate for 720p60 streams to 4500kbps. This is a reduction of 1500kbps or 25%. Effectively, non-partners must choose between the higher perceptual quality of 720p60 at 6000kbps, or lower perceptual quality at 4500kbps to also have transcodes. This is arbitrary.

3. Custom parameters allow for higher perceptual video quality, especially during high motion scenes. For example, according to EposVox, on RDNA2 & RDNA3 series GPUs, the highest perceptual video quality is achieved with 1 b-frame, and 2 b-frames results in the second-lowest perceptual video quality. To him, and also myself, the difference is visually noticeable, and it is significant.

My suggestion:

Allow Twitch Enhanced Broadcasting to, at a minimum, allow you to change source quality parameters, and at best, allow you to change all parameters for all tracks.