I had the same problem. I only had one or two consuls before all the other requirements for the reforms were accomplished, and the ones that were consul were not elegible for the 'Marius wannabe'.

I checked the traits file and saw that consuls also need 1 or more command stars. I deleted that line (since 2 out of 50 family members have a command star) and got more consuls since. (I once even had 3 consuls in the same season)