Okay, so here's something that happens with me and gives me a lot of frustration in my stream.

Scenario 1:

I love to stream some good ol' PS2 games, like Prince of Persia: Sands of Time, Onimusha, etc. Those games exist in Twitch Database, so, when I stream them, I put them games on the Category/Game tab. Then, I go for that "tags" section, and add the Retro tag on my stream, because it's an old game.

First issue: This tag will not show my old Prince of Persia stream in the Retro category, BECAUSE my game/category is... Prince of Persia (that will have basically 0 viewers in the entire world, and that's ok, it's an old game!).

The thing is: Why that "Retro" tag doesn't put my stream onto the Retro Category as well? People goes to Retro to watch old games, they could discover my stream by casually going there and "Oh, I used to love PS2, let's check this guy!".

Ok, so, Scenario 2:

I'm streaming PS2 games, and I do put my stream on the Retro Category. Ok, now people looking for old games can discover my channel. Let's say I'm streaming Gran Turismo now. I'll have two issues now!
1 - Due to the Retro Category being "tag-locked" as Arcade, I'm unable to tag my stream as "Racing Game", because Retro is "tag-locked" to Arcade.
2 - If anyone feels like watching some Gran Turismo 3 specificaly, going to the game's page will not show my stream, because I'm streaming Retro.

Not only that, you can add another BIG issue: Twitch Search Engine is really bad. It does not searching anything you want, it only searches channels. If I search for Dreamcast, i.e., it will not look into streams titles that say "[Dreamcast] Hello, Shenmue day, come watch".

My ideas are:
Retro tag puts your stream on the Retro Category as well the game's category;
You can tag your stream with the console you are streaming from, like DC, Genesis, etc, etc, etc;
Search engine gets enhanced with an option to actually search things, like I said, searching for Stream Titles that say something you're looking for.

Thank you in advance for everyone that struggles with that kind of problem and upvote this post.