What Moto phone do you have anyway? The OG Moto X recently got the fix along the with the Lollipop update and the Moto Droid Turbo just began soak tests today so it is probably coming to everyone within a week or two.
I am a Computer Systems Engineer and an Android developer as well as the proud owner of an OG Moto X DE, and I was utterly unconcerned about the 1st Stagefright vulnerability because of ASLR protection. With Stagefright 2.0 they claim they can get around ASLR, but this has yet to be proven by a 3rd party as far as I am aware. Anyway, it can all be mitigated by disabling auto-loading of MMS, which is what I assume you mean by "disabled functionality", which is how I have always configured my phones because I hate when someone texts you any random video and it automatically starts playing without your approval.