I remember the debate over using only Lego in one's brickfilms, and I wrote a piece about the option in my Brickfilmer's guide.  But I got out my old Homemaker figures and thought they'd make great Lego animation characters.  So I wrote a small piece on it which I'll be putting in future editions.  I hope someone who reads this will have a new world of Lego open to them!

What you can discover using your purist limitations

You're not really boxing yourself in.  Limiting yourself to just Lego, you can discover that you don't always have to have minifigures as your characters.  If you don't know about the following, why not discover these real Lego themes:

FABULAND.  These Duplo-scaled sets from the early 1980s featured anthropomorphized animals living together.  One Brickfilmer, ThaukaFilms, has a series of deductive mysteries mixing Fabuland characters with traditional Lego.  By the way, Duplo minifigures aren't out of the question.  Duplo bricks and even Quattro bricks are Lego-compatible.  If you need a quick wall, Duplo is your ticket!

HOMEMAKER FIGURES.  Before the minifigure, Lego made larger figures seen in, but not limited to, Lego's Homemaker series.  The Lego Group manufactured these figures from 1974 to about 1979 or 1980.  Iconic is set #200 from 1974, introducing a Homemaker family.  The Homemaker head size is 2x2x2 as opposed to the minifigures' 1x1x1 head.  Their chests are special 2x2 bricks modified to accommodate arm pieces and the head.  The rest of the body is brick-built.  I own a few of these from my childhood, albeit with some lost hands and broken 2x2 chests.  Like everything in older Lego, Homemaker scale is much larger, about twice that of minifigures in all dimensions.  I've had a renewed interest in my Homemaker figures and purchased additional parts on BrickLink.com.  It turns out that they aren't so expensive, possibly because demand is low.  But they must be pleasant to animate, and of course, tedious walk cycles are eliminated because the characters would just slide around your set on their 2x3 brick or plate monopod (foot).  Of course, you can construct moving legs using the myriad of smaller, movable piece combinations available today.

BIONICLE AND OTHER ACTION FIGURE SCALE.  What can I say?  They're semi-compatible with standard Lego, super-poseable, and great for action films.

EARLY BELLEVILLE.  These dolls originated in the mid-1990s and ran into the '00s. before their form was changed to a scale to around minifigure scale, and being replaced completely in 2012 by Lego Friends.  Animating with Belleville dolls keeps one strictly within the Lego building system but enables an animator to produce something with more of a "Robot Chicken" feel.  Even Nightly News At Nine used one in their films, "Robots! Robots! Robots!"  Oh, and speaking of Lego Friends: since it's been such a popular series, I'm surprised that you rarely see Friends' mini-Doll figures in Lego animation, and more girls aren't making brickfilms! 

BRICK-BUILT CHARACTERS.  Now, David Pagano of paganomation.com created a template for a large articulated figure.  You may like that, but how about going in the opposite direction?  Build your characters solely from bricks, plates, and slopes, avoiding all the specialty pieces that have arisen since the advent of the minifigure.  You can model them from Miniland scale figures, or just build something abstract, as those like myself and other children of the 1970s, who had a limited range of brick types.  Since there are no points of articulation, either parts must be changed around for each movement, or separate models are to be built for each frame of a cycle.  Either way, it is more work than animating a minifigure, but lends itself to making animations that are more artistic and abstract, and you might have an award-winning conceptual piece when you're through.

Exploring these themes, some very unorthodox, can be satisfying.  Moreover, since the average brickfilmer wasn't alive to see these themes during their production runs, discovering them goes a long way in helping younger brickfilmers to have a deeper understanding of the product's history, and even intrigue the viewers who never saw such pieces before!