I've been running a deck based on the concepts in this one for a couple months and love it. I also discovered going more all-in to humans makes it much more competitive and mainboarded Immolating Glare to buy time to get your profit-makers set up. My differences from this current version are as follows and for these reasons:

1) Mainboard creatures - I run 22 total using no less than 3 of Thraben, Lieutenant, Bygone, Mole, Tracker and Hamlet Captain. With 4 Graf Mole at a lower CMC than Heron's Grace I tend to have enough opportunity for life gain. Mole doesn't fall to Harnessed Lightning or Fiery Temper or Scrapheap Scrounger and that's important against aggressive decks.

2) Mainboard spells - I've also included Immolating Glare but added 2 Expose Evil (3rd in sideboard) because it really helps clear the way of the biggest blockers to make combat match-ups difficult for them, especially if I've got a lot of Human tokens that were pumped with the Collective Effort or Lieutenant. Expose Evil gets me to their planeswalkers that are often one of the biggest problems and with the Investigate part, in a mid-game situation means your not down any cards. It's also enjoyable to watch a 10/10 Colossus and his twin turn sideways and just run right past them with your armada.

I'm trying out Blossoming Defense as a time buyer against the aggressive decks with lots of early removal and doing so in lieu of Confront the Unknown. While it doesn't investigate it does put a crimp in their plans to clear out a high toughness blocker like Mole.

Aetherflux Reservoir - with all the clue sacs to Mole I not uncommonly have ridiculous life totals but cant push through Grafwidows or other token generators like Gideon. 1 copy in the mainboard as an alternate win condition. This is the only card with CMC more than 3 in the mainboard.

3) Flying defense weakness is a moderate problem. Copters on turn 2 and indestructible Avacyn's, Ormendahl's and Emrakuls all fall nicely to a timely-played Clip Wings and that's why I prefer it over Plummet. Most decks don't run a lot of flyers, but when they do those are the problem ones that only go the graveyard with Clip Wings (Stasis Snare can detain them but it costs more and it can be destroyed).

4) Sideboard differences - 2 Fragmentizes at the moment, no Root Out. The problem artifacts to take out are mostly 4 CMC or less - Copters and Panharmonicon are the ones I don't want sticking around.

I don't run high CMC cards like Journal or Enchant Creature spells like Gryff's Boon or Angelic Gift - too susceptible to removal or bounce spells that leave you with a card disadvantage. Instead I have 2 Fumigates for when things get desperate and if you have Mysteries out you get some value out of your creatures dying besides the life gain from the spell itself.

@crhousel

Thanks for your feedback! I like this kind of comments!

I should definitely try out your modification. Previously, this deck has been much slower but I managed to make it more aggro with Humans tribal theme (see this update). Still, it can perform very well if you have good opening hand (yesterday won against Madness Vampires at T5 cuz I was very lucky to get 2 Thalia's Lieutenants and 2 Thraben Inspectors). If you don't you will be smashed before 4th turn by any aggro deck.

How competitive is the variation you're running?

The deck holds its own against all archetypes in the Tournament Practice queue online. The matchup that is most difficult is probably BG Delirium but even there, short of mana hose, it's probably right around a 50% win percentage if you know what to look for from your opponent and how to respond when those threats come down.

Planeswalkers, flying creatures and mana hose are probably the most common problems but that's why the adjustments in the previous post have been so helpful.

General strategies as follows.

UW flash - they are playing for tempo, Blossoming Defense keeps your cards from being bounced by Reflector Mage, Bygone Bishop trumps or defends against everything but copters and Avacyn and that's why you play Clip Wings. Expose Evil and Immolating Glare slows them down if you can't stick anything in the early game.

BG delirium - don't fear the Flayer, let him get delirium and them take him out with Collected Effort while also pumping your army.

Emrakul defense - watch the card type count and mana and play out any cards of your hand that would be destructive to your own army (Collective Effort primarily) a turn or two before Emrakul can be cast or played with Marvel and have a Clip Wings ready if you suspect it's coming down soon. One game it played twice in a row and each time Clip Wings took it out.

UW Control - they have only 1 or 2 creature sets really, save your Collective Efforts for them and pummel with all the low CMC cards and clues you draw. Glimmer of Genius, and Gearhulk flashback mid game is inferior to all the clue draws this deck generates.

Red defense - even if I can cast a creature first, I will almost always lay down Mysteries first and then cast the creature so when Harnessed Lighting hits, all they've done is essentially traded a removal card for the ability to convert your creature into a clue that could in turn come back as another creature. Be very cautious of Radiant Flames, if you know they have them try to match the number of creatures you have on board that would die to it to the number your opponent has so you don't get too far behind on card count when it is played.

White defense - watch out for Cataclysmic Gearhulk. If they have them and you have a Tracker with clues on the table, keep the Tracker and choose to let all your clues get sacrificed to pump up your Tracker and get free cards without having to pay the 2 to crack each clue! So cool, I saw somebody else do this to themselves, they played the GC and kept it and their Tracker and ended up with 7 cards from a hand of zero, a massive Tracker and essentially a clear path to their opponent. I don't suggest playing the Gearhulk myself as it doesn't fit the synergy for this deck.