Probably a few pages back but here it is
I would say at higher ranks like that mirror entity isn't all that good, everybody assumes you have mirror entity and they play around it or worse steal it and screw you instead. So what I thought was that even if I don't have mirror entity it's like I have mirror entity and the real value in the card is that people will hesitate to play a minion on their curve and ruin their own play anyway. I replaced with other secrets, at some point I was running ice barrier and duplicate. Now duplicate and mad scientist don't play well together, you can't decide what to duplicate, that's a problem but it's a very powerful card when used on your belchers for example. So I suggest remove just one of the mirror entities only and use ice barrier instead, that gives you some longevity that deck like that could use. Ice block is great too if you have that. Normally when someone sees a mirror entity assumes the second one is same too, so it's very powerful like that.
The mage deck I'm playing is closer to this now but I think you don't have the cards for it. You can replace Sylvanas with Maexxna, it's about 70 percent as good I would say
just don't play it against priests for example, doesn't happen all that often, it's not great against patron warriors either, they can buff their berserker with it but still in most situations it's a card that disrupts the board in a similar fashion and a target for silence. ET is good too if you want to keep it, he acts like a soft taunt and gives immediate value. It's just that Sylvanas stays on the board for more than one turn but ET is removed immediately.
Ragnaros, replace with a pyroblast and use it as a finisher.
http://www.hearthpwn.com/decks/227207-eu-legend-1-tempo-mage-updated
don't do the three secret thing, I would include a mirror image instead for aggros and combo it with flamewaker if you can. Read the text too, some tips there.
