I don't see how the old system fostered competition. You weren't even competing against your opponent. You were seeing if you could eke out more banners vs your opponent than some other guy vs his. Your whole season could get derailed by 1 misclick or 1 opponent setting an eff you defense.
The crystal change, to me, is just a nice QOL that got me away from my hyperactive arena shard duties. Frankly, I might have quit without this change. IRL was really hectic for me in Feb/Mar, and I could not have kept up with my 7-10 SA battles every evening.