I hesitate to suggest this, since you say you don't like it, but I honestly think it's perfectly all right and it's what people in the field seem to say. I think the word "age" should probably be in there, since I presume they're saying there is a correlation with age (in years).

Here's Mayer himself:

"Finally, EI should develop with age."
http://www.unh.edu/emotional_intelligence/EI Assets/Reprints...
(Not searchable, apparently; the quotation is from the Google result.)

Salovey, Brackett and Mayer on their work:
"they [emotional skills] develop with age"
Emotional Intelligence: Key Readings on the Mayer and Salovey Model, p. 244
http://books.google.es/books?id=YVKmxr_D7yQC&pg=PT217&lpg=PT...

Mayer again:
"according to EI theory, these skills develop with age and experience"
http://therulerapproach.org/images/uploads/documents/Rivers_...
File not found, quotation from Google result.

And there are more; it's what people tend to say when referring to the work of Mayer et al. I think you can safely settle for it; it's OK, really.

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Note added at 1 hr (2013-10-02 19:51:31 GMT)
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I know just what you mean, Peter. The trouble is, I find, that when you are worrying over an expression you quite soon lose the ability to tell whether it sounds right or not.