I'm getting pretty frustrated of taking not EZ ranged AD and having the bruisers jump right through the tanks, beat me up, and then jump right through the tanks out. An item that deals with this situation would dramatically increase my enjoyment of this type of champion.
Maybe if Cleanse was changed to help against all CC (fk you Nunu/Singed slow, Exhaust damage reduction debuff, Malz/Skarner ult, Wukong/Alistar knockup) it would disproportionately benefit champions without CC and a weakness to CC *cough* carries *cough*.
Other than that I don't see how a mobility-granting item could be niche enough for only carries to grab it. If it offers solid AD stats anything that scales with AD will grab it for the free Flash, if it's expensive enough to need serious commitment in a build you won't have it for half the match, if it's cheap enough to utilize early everyone will get it (and complain on the forums that the stats don't jive perfectly with their choice champ).