I don't see any immediate reason why this should lead to more spam (assuming you're talking about the 2 hour window change). If you're talking about going back to straight linear vs quasi-linear, I think it had no real impact on spam either.

The proposed change will still have the end result be that a few content creators will consistently get all the votes.

As auto-voted stake will likely be guided more by humans reading posts than by a simple list of authors after this change, it should spread the rewards more equitably among authors. How well it ends up distributing that stake among a large group of authors should mainly depend on the number of quality authors.