If you have such a reduced experience on the embeds compared to watching on Twitch.tv, then watching through the embeds is useless really.
The restricted embeds will basically limit them to simple usage like social media embedding only, and if you actually want to create a separate and special off-site experience, you’re out of luck because the experience will be so limited.
There are plenty of legitimate sites who use the embeds for a full viewing experience, like multi-stream sites, collaborative-watching sites, team sites etc.
It’s a shame if the user has to be punished for watching through those sites.
As for the “abuse”, if there really was proven to be such a mass spread abuse, it would be pretty simple to restrict the accumulation to X channels at a time. I can think of a handful other, much easier, ways to “abuse” the system besides embedding.