I really wish IPv6 had a better argument than you can't get IPv4 addresses needed to build a complex application.

The majority of complex applications being built today are being built to be IPv4 accessible and may even be using IPv4.

You can use 17 million private addresses + buy plenty of public IPv4 addresses.

AWS and Google are both building major clouds that are both complex and STILL heavily IPv4 oriented (I and others pinging them to add IPv6 for a long time).

They throw in an IPv4 for every running instance and even their elastic IPv4's are cheap if attached to an instance.

It reenables all of the devices on the internet to be able to directly connect to each other. No NAT, no STUN etc.

Do we even want that anymore and is it still a smart idea?

We actually do want that especially for the internet of things, so that your lights and garage door keep functioning during an AWS outage that takes out the relay servers (used to work around NAT) or if the manufacturer goes out of business.

That decision should be taken by filtering (or just preventing it altogether) in each specific case. With dynamic IPs, it's already a no from the start.