I think you definitely had a Bant deck hidden in there with all the guildgates and defensive creatures, although I'm surprised you didn't do better. Your current deck (minus the croc) looked pretty good.
I lost match one to the mirror because he had Rakdos and none of my removal kills Rakdos (I sided in Launch Party just to have an out in game 2, but it didn't show up).
I lost match two to a Golgari grind-em-out deck in which I mulliganed at least once each game. I also completely underestimated the Golgari guildmage; I left it on the table because the first ability wasn't relevant (since my guys weren't blocking anyway), but failed to appreciate just how powerful the second ability really is.
I lost a close match three to UW skies, again with mulligans and the fact that my mana base wasn't correct (I would have won the match in game two had that meaningless Forest been the Swamp that I cut for it, and M3G3 he played a T4 Jace with defense on the board).
The lessons I learned:
1) Don't splash for anything other than a bomb. The reward is not worth the risk.
2) Even in an aggressive deck, it's better to have solid mana (I had two Rakdos Guildgates and only ran one because I was worried about temp loss).
3) I absolutely agree that I would have been better off to have added all the removal to my deck. I definitely locked myself into a narrow view of what my deck should look like and missed some angles that would have improved my deck.
4) I also realized that combat with the Rakdos deck is very difficult once each side has more than 2-3 creatures on it. Once again, more removal would have been better.
In short: I probably didn't mulligan correctly, absolutely could have built a better deck, and made a couple of small play mistakes. The mistakes I made were marginal, and in most games I had outs, but I won't blame luck when there are obvious mistakes I made that didn't put me in the best position to win.