ACARS... I think we can read too much into this. 1 type, in 1 airline, with 1 ACARS service provider / type, happens to provide some interesting messages. In the absence of anything else, these have proved useful to Investigators.
That's a long step from "mandating" a standard across all airlines / types a data stream and protocol that is used for "flight monitoring". For starters, not all types/airlines will use Satcom for ACARS, and it is not cheap. I work for a large UK company, and one of our LH types only has ACARS via VHF (or did when I flew it). If the ACARS is in VHF comms, then so generally will the crew...
For those using the various ACARS systems, they frequently go to standby, or someone retunes / uses VHF3 etc. To call out the full SAR system for a mid ocean rescue everytime the ACARS / Satcom goes on the blink will keep them well occupied
Accidents / incidents such as this are relatively rare, and the cost of uploading effectively FDR type information via satellite will not be trivial across the whole world's fleets. Far rarer will be the occasion it makes 1 jot of difference to survivability.
Knowing "what" downed this A330 is of interest to pPrune readers, and also to AF, Airbus and the families. But is it (or will it turn out to be?) so necessary as to enforce FDR data uploads? The cost and delay of the search is significant, but I suspect small compared to implementing such systems.