The linked FAQ in the article says: "terminal multiplexers are a bad idea, do not use them, if at all possible".
This sounds like the author seems to ignore the ground reality. For the vast majority of users, tmux simply does its job and gets out of the way. They (we) don't even notice these subtle issues. It's simply a non-issue.
Stuffing the entire multiplexer into a new terminal emulator sounds like a solution in search of a (specialized) problem. Not just that, you now have two problems: first, you have to learn the new terminal emulator; then, get to the built-in multiplexer with its own quirks.
This sounds like the author seems to ignore the ground reality. For the vast majority of users, tmux simply does its job and gets out of the way. They (we) don't even notice these subtle issues. It's simply a non-issue.
Stuffing the entire multiplexer into a new terminal emulator sounds like a solution in search of a (specialized) problem. Not just that, you now have two problems: first, you have to learn the new terminal emulator; then, get to the built-in multiplexer with its own quirks.
The classic cliché of "do one thing and do it well" applies here.