I think the overall effect of ICOs will depend on how many live up to their promises (or at the very least, die trying).

ICO tokens are pure inflation, and the value placed on them today is a guess at future utility. To the degree they produce utility, they will have a positive impact on the space. They seem to be part of what is attracting so much new money into crypto right now, but if too many people get burned, that will hurt crypto in general.