After unifying the WBC and WBA world strawweight titles, Kazuto Ioka immediately vacated his thrice defended WBC belt. Unless your name is Wladimir Klitschko, you're not likely to hold on to 2 or more of the 4 major sanctioning body titles for long in this day and age. Sanctioning bodies often demand mandatory defenses within an unmanageable period of time against different opponents, as each organization's "world ratings" tend to be quite different.
The WBC in particular has been most adamant to not uphold unifications, often telling unifying participants beforehand that they must give up one of their titles afterward, as was the case with Amir Khan vs Danny Garcia. The WBA felt Amir Khan deserved an immediate opportunity to regain his super title after stripping Lamont Peterson for illegally using synthetic testosterone prior to their December 2011 encounter. Apparently unbeknownst to Jose Sulaiman at the time, the super WBA title doesn't come with mandatory defenses like the regular title. Thus, Garcia actually will defend titles of each organization against Erik Morales later this month.
Getting back on topic, Ioka has more recently vacated his WBA title as he's decided to move up to the light flyweight division, where Roman Gonzalez reigns as the WBA champion. The WBA reports that Ioka has been elevated to the #2 WBA light flyweight rating, behind interim champion Alberto Rossel. Gonzalez, fresh off a 3 round rout of Stiven Monterrosa, is widely recognized as the best fighter in the division. A meeting between two highly regarded, undefeated world champions such as Ioka and Gonzalez is the type of fight that could put the underappreciated light flyweight weight class on the map and, "more" importantly, catapult the winner to worldwide pound for pound recognition.
Personally I just think Gonzalez-Ioka is a great fight and would love to see it. Let's hope it happens.