Authority Site Based On Lower Amount Keywords

Would it be an effective strategy to build a niche site on a broad niche and find many different keywords that are between 250-1500 local searches per month with nearly no competition. I was thinking about doing this and I can't seem to find anything that would be bad about this idea.

I was thinking I would probably have around 60-500 different articles each going after keywords that are 250-1500 searches per month. Is there anything I'm missing?