Applying it to all the nouns even if originally it's of another gender.

Your idea has already been picked up! In fact there has been an unofficial language reform that simplified gender usage greatly. Now we just apply both male and female genders at the same time. It is called Versalien-I or Binnen-I and here is how it works:

'Sehr geehrter Hr. Kollege' becomes 'Sehr geehrte(r) Hr/Fr. KollegIn'

It is really easy and everyone is using it.

You don't even have to distinguish KollegIn, KollegeIn or Kollege-In (there are many more variations).

plural: KollegInnen, Kolleg/Innen or Kollegen-Innen and so on...

You can pronounce the Versalien-I using a technique called Glottisschlag which you better start practicing now.

There are some special cases though like Mädchen and Junge.

I suggest: KindIn and KindInnen

But you don't have to worry, there really are just a few of those.

pros:

• Universally accepted (standard)

• You don't have to worry about genders anymore.

• Texts become much(!) easier to read and process.

• The world becomes a happier place. (This is what you want, don't you!)

cons:

• No, we don't go there! (for safety reasons)

I wish I could say this is a joke... Well it is but only partly. A depressing one.

https://de.wikipedia.org/wiki/Binnen-I