After reading some of the comments here, I have to confess that I agree with them to a certain degree. While your film was still highly enjoyable, it nevertheless felt like it was lacking something that I couldn't quite put my finger on, but now I realise what it is. It just seemed a tad too formulaic and repetitive. There was no real driving force or build-up in the film, and it was more or less a bunch of jokes strung together, as others have pointed out. Despite the enjoyable randomness of it, the film was too repetitive (Garry sits down on park bench, leprechaun appears, randomness ensues, Garry screams something random).
It's not the randomness or weird characters per se (you are wonderfully good at making those), but it lacked some sort of driving plot behind that would make it a lot more coherent. It doesn't have to be excessive exposition or a detailed back-story (although I'd really love to see more of your back-stories if possible), there just needs to be some sort of motivation for the characters to carry the story forward.
For instance, Garry might have forgotten who he was or somehow realised he has magical powers, and wants to find out why this is the case, so he sits down on a park bench to think it over. Then Fred appears and tells him something important about him. Now all of a sudden the random appearance of Fred has some significance within the plot, makes the whole story more coherent, and creates a build-up towards the climax of the story. (OK, this is a really bad example, but hopefully you understand what I'm trying to get across.) Randomness is great, but on its own it can't carry an entire story. If there's no build-up towards a climax, the end of the story kinda fizzes out and feels weak.
I think one of the problems though is that it's too similar to your other films. It has the same structure: omniscient 3rd-person narrator (who is always Sonjira--not that I have anything against him) opening with the lines "once upon a time", a storybook feel, and general fairy-tale atmosphere. While I love the style and you make it work very well, you've used the same style over and over again in your films, and at this point it's beginning to feel a bit stale. Also, constantly using a narrator can tend to overshadow the characters themselves and stifle room for their development. Since an omniscient 3rd-person narrator sees everything, it kills off any ambiguity, which is sometimes (but not always) bad since good stories often have a touch of ambiguity. What I'm trying to say is that this style is not bad inherently but I would like to see you try something new and different for a change. Not necessarily something majorly different but perhaps something with a somewhat different style, e.g. something perhaps less overtly fairy-tale like or without a narrator. (On a side note, I'd be really interested to see how you'd tackle a serious brickfilm).
However, you did mention you wrote the script over 2 years ago, so I think this feeling may also have to do with that.
Anyway, as I mentioned before, this film is great technically (in fact, probably one of your best), and the animation is beautifully smooth (i only wish I was half as good as you). But I do think it would be nice to see something different from you, and while Leprechauns in France is a lovely brickfilm it is beginning to feel repetitive (I mean, you used the exact same style in Sharks & Clowns, Odoriferous, The Lost Invention, and LiF, along with Planet of the Sneeuwpop, which is about half of your films). I hope you don't mind my excessively long post.
Irish leprechauns are generally like normal people and don't seem especially special, though they do actually speak in their correct accent. However, Irish leprechauns hold an almost American obsession with guns, and also have the habit of acting quite polite then shooting people on a whim.
Just a thought: shouldn't American Leprechauns be the ones obsessed with guns, then?
Retribution (3rd place in BRAWL 2015)
&Smeagol make the most of being surrounded by single, educated women your own age on a regular basis in college
AquaMorph I dunno women are expensive