As a small market pursuer, I had to say that a tiny market is different from tiny effort.

I developed torapp guilloche designer (http://www.torapp.info) for security printing industry, which is definitely a tiny market. But it did not mean less competition, and it is in fact much more complicated than a regular graphic editor like adobe illustrator and coreldraw.

Besides regular editing facilities in AI or coreldraw, I spent tremendous effort to handle all possible math formulas/curves as comupter algebraic system (CAS).

I would recommend people to pursue as big market as possible.