You may want to try adding a few borderposts (
Mistvein Borderpost 
) as an easy way to have a multicolored card for your stormblade (as well as have a kind of color fixer.
I'm not so sure
Zealous Guardian 
and
Oona's Gatewarden 
do enough. Gatewarden is fine if you really need to stop aggressive creatures, but it doesn't have all that much synergy otherwise. Something like
Spellstutter sprite 
would make having a faerie a good idea.
The Guardian could be something else entirely, almost any creature would be better, it has very little synergy, it doesn't trigger your mimic and it doesn't get the full bonus from your edge of the divinity. Even switching 2 of the guardians for 2 more Nip Gwyllions would probably be a good idea. Also, something like
Doom Blade 
or
Recoil 
to remove problem permanents that slip through your counterspells could be a good idea.
I think 24 lands may be a bit too high, you don't have anything that costs more than 2 mana, plus you have some cantrips, so 21-22 lands might be better, though I could see how you'd want to be at 3-4 lands to play a creature and leave up counterspell mana.
I think esper panorama might be a mistake. It looks better than
Terramorphic Expanse 
/
Evolving Wilds 
at first glance, because you can tap it for colorless mana if you really need the mana that turn (though it's slower if you want to just use it to fetch up a land). However, if you look at the cards that are actually being played, everything uses colored mana except the mimic and the mana leak. Thus, I think it would actually be faster to use the Terramorphic/Wilds in stead of the panorama, because you don't need a second land to pay for the cost of sacrificing, like you do with the Panorama.
Hope that helps!
