IN OTHER WORDS:
Stop freaking out about them.
Did Mass Effect 3’s ability to buy requisition packs kill its multiplayer? Not at all! The REQ packs for Halo 5 only (and this is quite minimally, I might add) effect Warzone mode; Arena mode absolutely will not be affected by REQ packs outside of cosmetic differences players get.
Besides, you guys get free DLC map packs because of this system - would you rather everybody pay for maps and nobody has access to REQ pack purchases which only marginally impact Warzone or some people who choose to buy REQ packs and everybody gets free map DLC?
Just some food for thought.
And you can try and spin this in any way you want - I’ve seen games I loved ruined by microtransactions and I’ve seen games I love benefit from a smart implementation of microtransactions. This appears very similar to Mass Effect 3’s methodology for employing them, so I’m not too concerned.