First of all we players are watchers of the development, not directors. We don't decide what the direction of the game is, there is no popular vote for features.
Secondly the feature list (plus/minus some minor features) seems to be quite finished by TFP. They have an internal priority list with bandits on top. Presumably a lot of features that had already some development put into them, like legendary weapons, will also be high on that list. You can post your opinion a hundred times and it will not change that internal priority list.
Thirdly one of the things that definitely will be done will be further optimizations. But the chance that it will bring zombie amounts like in the mentioned games is practically zero. This might increase zombie numbers slightly but not by much (since they always have to tune everything for minimal spec PCs).
They probably will add one or two options into the game that allow to change zombie numbers better than now, but that's it. Also the option for zombie sensing range that will come with A20 will help. If thats not enough for you your only option will be mods. Mods are the **official** way to prolong the relevance of this game, that is the reason TFP put so much effort into making this game easy to mod.