you are right ! sending the same article to many directories wont help too much , not because any penalty , but will just have indexing problems since google just does not like duplicate content , also the links on those pages will be less valuable .
you have basically 2 good options : the best will be to send different unique article to each directory , thats the best option but might be a bit expensive to implement , the second best option and what most people do - is to spin the article with different text spinning softwares to give it at least 40% uniqueness and that way it will have much better chances to look like a unique article to the search engines .