Not really. I mean, we do not all want to be labeled just another ID do we? If the community gets large then that is how it would be like. In every server we join we see a familiar face. If the community were to get to large, There would always be some new person in a server than you wouldn't really want to get to know, cause you know you might not ever see them again.
There are some reasons to like a small community. And some reasons to want a larger one. For both of them, there isn't really a selfish reason on either side. People who want smaller communities Prefer the ability to know each other and see their friends on a different server upon joining. and we all know we do not want to be labeled as "just another ID".
I must admit that there is some kind of sense in this.
The reason this community is so good here at the moment is because the community is small.
Compare it to a town.
In a small town everyone knows each other (or at least, that's what they say).
But in a big city, most people don't even know their neighbors. :P
So yeah, there is some kind of sense.
You can see it in forums of big games with a lot of people.
Those can have a nice community too, but it has a bigger chance of being less... like what we have now.
A change in the size of the community has an unpredictable effect on the community.
As long as we are willing to accept them into our community, it should be fine.
But if people for any reason, don't accept the newcomers, the community will be split apart.
It also can become a community where some know each other very well and some don't.
Practically, a larger version of what we have now.
Just my thoughts on it. :)
TL;DR
Submitting Blockland to Steam isn't a bad idea.
The community will stay the same, but bigger as long as we are not acting solitary.
Don't be afraid of change. ;)