All these technical talks really confused the heck out of everbody- let's keep it simple:

1). If all the sudden we double the miners on the blockchain -  Please stop zooming in to the details, such as how difficult to get ASIC machines, blah blah blah.  Let's take a straight senerio where if we double up the miners in blockchain, it will definitely reduce the blockchain back log - by simple supply/ demand law it will reduce fees and less unconfirmed transactions - period !

2). Please keep in mind I'm not talking about the additional private miners for profit or become a business.  I'm only talking about bitcoin owners running mining machines to protect their bitcoins investment and defend the only true decentralization cryptocurrency vs the rest of fake centralized cryptocurrencies.  This is sad that I have to use the term "decentralized cryptocurrency", which is kind of redundant - as there are so many fake cryptocurrencies that are,  in true mean are not cryptocurrencies at all !

3). Now if there are more miners on blockchain, I suppose you'd get less chance of winning bitcoin, but you are not seaking for profit and just simply trying keep the blockchain decentralized and protect your bitcoin investment, think it would worth the effort...