Teching is a lot easier said than done. You, as a top 200 legend player, should know that.
Playing an EMP operative may MARGINALLY increase your winrate against mech decks, but you have to take out a card. That card is most likely 10 times better in any other matchup. Congratulations, you just increased your winrate against two archtypes by 5 percent and decreased it against eveything else by 10%.
Tech cards should be "acceptable" drops on curve, or tech against a big enough portion of the meta that the net effect is a increase of your winrate. E.g. MC tech in the last meta, ooze currently, etc. Or it should be a crucial tech for a certain matchup that may be your biggest issue, like Elysiana for control vs control, since control is going to have a fine time against aggro anyway.
Now with regards to your tips: Token druid summons well over 4 waves of minions if you don't establish enough tempo to stop them from doing that. Putting in 6+ drops that deal with a single wave is not going to do it. Best way to prevent those waves is to be ahead on the board, in my experience.
Against res priest, hex or polymorph are far better than running a card than, for 90% of matchups, is absolutely atrocious. Yes, those are class cards, but sometimes it's better to tech against the meta by playing certain decks, rather than butchering your current deck.
Against bomb warrior, Elyssiana is the given tech, since bomb warrior wins near fatigue. If you are playing tempo, than you don't even need to tech against it. You are not going to put in a bunch of mechs into your tempo rogue as a tech against bomb warrior, are you kidding me? If anything spectral cutlass might be decent as a source of healing that can also push face in other matchups. And playing mech hunter is a good way to counter the bomb meta.