Software development does not fall into the category of inventing but rather of skillful development of large works, just as the term suggests. It makes no sense to extend a legal instrument designed for technical inventions into the area of software, which is what the EU Commission's proposal actually does.
Supporters of the EU-Directive bring forward that legal security will increase and a unification of the presently different legal positions in several member states will arise. The objectors, on the other hand, fear an enormous aggravation for the European medium sized enterprises. The design of new software would be limited. As the EU-Directive is similar to regulations in the United States of America big enterprises would try to avoid the competition.
see Tang, Adams, Paré 2000: Patent Protection of Computer Programs