Ryan Cleven (Lead Design Developer for Multiplayer) said last night on the developer stream, answering my question in fact that they want to implement the progression feature, but their system was entirely made from scratch, and by the time they were working on that feature, it ran up to launch and they had no time left.
Their initial plans were to use both progression and the card system. If they do this for Gears 5 I won’t mind the card system coming back, just hope it doesn’t dictate and cuts down the amount of characters we can unlock via progression.
Another question was asked which feature was the one he wished got implemented into the game and he brought progression up, saying how he regrets that it wasn’t put into the final game. And the challenges how to unlock Griffin, Classic Golden Gear, Diamond/Emerald Gear he also said how he wished they did challenges like this from launch.
This has increased my confidence and I do hope they get around to it in Gears 5. I’m sure we won’t be disapppointed.