It gives incentives to run all four encounters every week, true, but let's say that I'm done gearing one job and now I want to move to another, but here's the catch - let's say the only thing I need is the top. BiS for this tier or what not. Before I'd have to wait an entire month for it. Now all I need is a week, getting my token from each separate encounter.
Running all encounters for a week vs. running the one encounter for a month, is the consideration that makes me think they won't do it. The illusion of shortening the content's lifespan

I sure hope they do, mind, especially with them peppering extra drops into the different fights like minions, orchestrion rolls and crafting mats.
Also, while I don't see them homogenizing the drops for the current tier, I certainly see no reason for them to not do that for older content. Even if someone wins all 4 tokens, it's old content people probably already run unsynced or through roulette in the first place.