Every famous thing dies at some point. Im almost surprised that didn't happen to Whatsapp.
Whatsapps big hype! FOR WHAT?
I don't really understand the big hype that surrounded Whatsapp at the start. Some people managed to write 60,000+ messages per day. I mean. Those guys and girls must be sitting with multiples phones at the desk and typing non-stop. HOW? The elephant is in the room, people got unecessarily hype and even addicted for chatting with someone else. Something that Facebook, Telegram, Discord, Slack all do today.
Too big to go down that easily
People are too lazy. For example: Apple changed the notification center in iOS so that it's only saying that there are new messages until the user unlocks the phone. Only then the user can read the content of the message. Some people got unnecessarely angry at that, instead of spending 1 single minute, googling about that. Turns out, there is a setting in the settings app to show the content of the notifications in notification center. Takes around 20 seconds to change that setting.
Whatsapp stickers: Non-inovational Idea with the worst possible way to implement them.
Let's be honest. The Whatsapp sticker that were added with the latest update are strange. You need to download an app that adds those stickers. It's a complete mess when it comes to such apps. And I guess there are already apps to search and add multiple packs but one trump sticker pack for example, comes in it's own app, which can be deleted after you added the pack. And sticker packs aren't even new. Telegram had them since years and had an in-app implementation for added and managing sticker packs. It's just ununderstandable for me how Whatsapp manages to fail so hard.
Whatsapp security. Existense?
As Whatsapp started, it sent every message unencrypted. At this time no one cared about security that much as we do now not even having an encrypted data? SSL/TLS would have been easy to implement. They only added that later as well as the end-to-end encryption.
Non-secret telephone number.
The next thing. The telephone number is not secret. If I want to communicate without the other knowing my telephone number then I can't use Whatsapp. Telegram solved this problem with their usernames and if you don't specify a username you will be invisible to strangers.
But in the end, even I have to use it because most people aren't using the alternatives. Some of them aren't even aware of Telegram, Threema or Discord.