Pretty much all of the evidence we have available from ME3MP and DAMP suggests that this would be a trainwreck.
Most importantly, basic things like infrastructure, resources, staff, balance attention and more are almost certainly just not there for PvP in ME:A. They were barely sufficient to support single-mode PvE crawl/wave content in ME3 or DA:I (probably insufficient in the case of DAMP). Not to mention that entirely new resources have to be scrounged up somewhere in the company (when the game has just been significantly delayed already) for PvP-exclusive things like matchmaking and, if this isn't going to be a complete farce, dedicated servers. Relatedly, some foundational decisions like making DAMP entirely about grinding to become a ball of stats are headscratchers that make me wonder what the design decisionmaking process is like at higher level. When the last lights were turned out at the offices of ME3MP and DAMP, both games had been left with myriad highly significant bugs and in an atrocious balance state (especially if placed within some kind of hypothetical PvP context). Finally, BioWare have demonstrated a keen interest in deeply embedding their multiplayer campaigns in the lore of the single player campaign, which is easy to do with PvE but isn't so much with PvP unless ME:A is unexpectedly the story of some kind of civil war or leadership conflict between factions of colonists.
Trust me, we don't want this in the slightest. Sticking very close to the model of ME3MP and improving it in a workmanlike manner in a new engine is a far better option.
P.S. Not incidentally, I also feel PvE is superior as an MP choice in this case because it's more inclusive to more people who buy these games for the SP. This aside from all the practical considerations I've listed.