Great spot to add my ideas not that they matter but it is an opinion, as my views have changed over time i have to agree not everyone will be happy with changes. As for myself the vanilla game is pretty much there as far as content goes, other content i can add via mods.
Other then that i think optimizing the engine, features like 3d wielded items, entities (mobs-logic), biome atmosphere/temperatures, weather and things like that should be the main focus of additions to the main game. However this is just my opinion and boils down to what PilzAdam was saying, some may not want certain changes to the main game.
Whether we all like it or not the day will come where the vanilla minetest game will have features you do not want. Some sooner then later, it is that far in development now that forks will be the only way to keep the majority happy.
There is a catch with taking the keep everyone happy road though. One problem is there is no set direction/path the game is heading, this could be the achilles heel/ backbone breaker. Close source game developers add what they think is beneficial not always what fans want. Close source games it is a tough titties situation if you do not like a feature, the developers have a direction they are heading to prolong development.
Very controversial topic as some are happy, others want more or less. The question is what road do we take? Keep everyone happy? or best interest in development and not alienating new users with a very basic vanilla game? Personally i am glad it is not my decision.