I suggested colons optional a long time ago after reading about it being optional in another language. The concept was down voted by most, maybe views have moved but I doubt it.
In some situations you can omit brackets when code is on a single line, I think this should work…
for (i in 0...new_word.length) if(new_word[i] == 'I') new_word[i] = 'You';
These types of changes your requesting don’t really add much to Haxe they can be considered syntatic sugar and mostly at odds with Nicolas vision since they can remove clarity in that spaces and returns are not considered enough, atleast as far as I understand, they would also as Dan points out be easy source of new bugs for little gain.
Often when approaching a different language we want to change it more to what we are used to, but really we need to embrace how it works currently and create stuff with it - only then do we start to really see where changes are most needed. These ones not so much importance, they may make it easier to code Haxe like Python but that only diverges the possible styles of haxe code increasing the cognative overhead to new users, definitely such changes would be at odds with current language consideration of easy adoption, while it seems easy to you less so for say a java or c# dev.
It maybe possible to get your IDE to hide colons and brackets fairly easily, this is likely the most feasible option for you to consider.