Leave a bit of space next to the rightmost tab...

[prino]

...so that you can CEA open a new tab by double clicking on it. Probably 10 pixels (or maybe even 5) would do the trick. Of course Ctrl-T also does it, but with the "T" in the middle of the keyboard, that's relatively speaking, harder than a double click.

[jupe]

Couldn't you just set the "New Tab" button to right hand side of tab bar? that would give you the pixels you want when required, and would only require a single click, and you could still keep the double click blank space enabled for when you have room to use it.

Configuration | Tabs and Panes | Tabs | Show 'New Tab' button [✔]
Configuration | Tabs and Panes | Tabs | Buttons position == Right end of tab bar