No doubt, yet these tools still maintain a huge mindshare and are very important to many communities.
I would love for you to explain to me how censoring words for myself has any avenue of abuse. Is muting users abusive then? And comparing highlighting some messages in a chat you’re in to automated monitoring of all chats on the site is just nonsense. If you want to abuse along these lines then you just use a bot.
Agreed, although it’s kind of a joke considering how most platforms still don’t even support displaying chat at all. 2018 and I’m still stuck casting a whole screen to get Twitch with chat on my TV.
Which is why I’m pretty grateful for FFZ features like chat batching that actually decreases lag on my crusty old laptop, minimalistic UI to get rid of all the pointless padding that makes less of chat visible especially at smaller window sizes, and portrait mode which is an absolute godsend for my vertical monitor. Ironically, this setup makes Twitch on my desktop much more consistent with the mobile app’s layout…soooo, what was that about disparity between platforms? 
Trust me, I’m acutely aware of all that goes into supporting new features, and never suggested the hundreds of options these extensions bring should all be built-in. That’s precisely why they’re important. Still, there are clearly a ton of improvements that could be made to chat, and if some unpaid developers with no choice but to hack on a system working against them can accomplish so much, then it’s hard to make excuses for a team of six-figure devs backed by the largest company in the world.