Seconded. Please do this. Thank you!

I would really like to see all purple plugins work in telepathy. (skypeweb, facebook, hangouts, wahtsapp...)

This seems a very good wish. But it looks like this component has been in active development for a while now. Just mark my wish here.

Looks like whatsapp-purple is no longer being developed.

However it seems that you can use telepathy-haze with purple plugins to some extent. I just found a way to enable facebook chat integration through purple-facebook.

See:
https://bbs.archlinux.org/viewtopic.php?id=208214

"Installed: 
purple-facebook-git (AUR)
telepathy-haze

I've created two files:
/usr/share/accounts/services/kde/ktp-haze-facebook-im.service

<?xml version="1.0" encoding="UTF-8"?>
<service id="ktp-haze-facebook-im">
  <type>IM</type>
  
  <name>Chat</name>
  <icon>im-facebook</icon>
  <provider>ktp-haze-facebook</provider>
  <translations>kaccounts-providers</translations>

  <template>
      <group name="telepathy">
          <setting name="manager">haze</setting>
          <setting name="protocol">facebook</setting>
      </group>
      <group name="auth">
          <setting name="method">password</setting>
          <setting name="mechanism">password</setting>
      </group>
  </template>
</service>

and
/usr/share/accounts/providers/kde/ktp-haze-facebook.provider

<?xml version="1.0" encoding="UTF-8"?>
<provider id="ktp-haze-facebook">
    <name>Facebook</name>
    <icon>im-facebook</icon>
    
    <description>Chat account in Facebook</description>
    <translations>kaccounts-providers</translations>
    <plugin>ktpaccountskcm_plugin_kaccounts</plugin>
</provider>

That is it. After that you can add facebook to in Online Accounts.
The only problem is that group chats do not work."

Could this be automated somehow so you don't have to search for this solution and do it manually?
Getting the other plugins to work would also be really nice.