I wouldn't agree that limiting the size of the model will do much for increasing participation. I started with a 3DHS Osiris that AJ designed and in reasonably short order, bought a SebArt Wind S Pro 2M ship.
I went to my first competition it was with the Wind flying in Sportsman. I did this jump as I knew I wanted to keep flying Pattern and it seemed unreasonable to go through a bunch of less expensive models when I could afford to go with the Wind. We've got guys around here flying mostly 2M ships like the EF Vanquish. Most were purchased from other guys who were moving up. If you restrict the model size for the lower classes, it'll mess up that natural progression of guys wanting to get a 2M and those who want to go to a more expensive airframe.
Personally, I think it might be better to encourage those interested, to fly what ever they already have initially. Then the smaller Pattern models like the Osiris which is no longer available, but AJ just came out with a Pattern model a lot like the Osiris but with a canalizer and it's $400.00. These little models fly very well and will usually be enough to get someone hooked if they already have any kind of interest. I still let new guys who are interested, fly my Osiris. They've all loved the little beastie.
I think that being approachable at the field will help a lot. Since we've had a certain guy show up in our area, the interest in Pattern has exploded. It's also a good primer for turbines, some of us have gone there as well....