It's bad for both sides. Seemingly unannounced change and unknown to nearly everyone. From a 2 person minimum to a 5 person minimum for the raid alert to show in chat.

Streamers don't get to welcome new arrivals and may appear as if they are ignoring the raid.

Raiders can feel like they aren't wanted and why bother raiding unless you have double digits (there's no way for them to know the limit is 5).

I can share this from today. I messaged a raider after checking the activity list before a stream ended and saw they had just raided with a party of 3, a few mins before. I explained the change with twitch, the limit of 5 ppl raids and apologised on behalf of the streamer for not acknowledging it.

I got this later.

"Oohh that’s okay! Thank you for letting me know! It was the first time I raided so I wasn’t sure if it worked. Thank you sooo much."