miner centralization only matters when one of the pools reach majority.
I don't believe that will ever happen. I can imagine that let's say 20% of home heaters use miners soon(tm). That's enormous amount of PoW. And Datum is a good way to give back control over templates to those miners and to fight centralization.
BTC users won't join any pool nearing control.
This core/knots fight is silly but I don't understand why core devs are so afraid of alternative client. It worked well for bittorrent, edonkey and many other protocols.