Mining is already sufficiently decentralized. Game theory dictate the structure will remain close to the current landscape. There will always be a few big miners. It's nice to have more little guys but it won't make Bitcoin any more secure to have more decentralization of miners. It will make it more secure just based on their being more hashrate. Mining decentralization matters most geographically, not so much separate actors. Regardless, mining isn't an issue imo and I wrote an article recently if you're interested in reading it. Bitcoin is built to withstand any concern in this field. It's own immune system is the only thing that fixes it, and it does so every time. No single pool or actor is going to magically make anything better or more resilient. Bitcoin will do that on its own.