Any chance of making fire not be put out with hand/tool, but require flowing water or block place? This would make fire more of a challenge.

Thanks

The new 6.0.5 update was released which partially addresses your request. There is now a config which allows you to prevent players from punching out the fire blocks. Fire can still be put out in a number of other ways, but there is no sane or reasonable way to account for all of them. This new config option is off by default.