... if this runs counter to the idea of a move to more decentralization.
No. The proposal encourages greater decentralisation. Right now it takes a lot of resources to run a seed node and so very few people do it. Moves, like this proposal, lower the bar for running servers and if the costs reduce enough there will be more public (and private) API nodes. Since API nodes are currently a major point of centralisation, having more will make Steem more decentralised.