What I really like with a text editor (or IDE) is to be able to easily remap its keyboard shortcuts to what I want, and Xcode seems to do a bad job with this.

I want to be able to switch file tabs by using option command arrow (left and right arrows). However, when I try to change keyboard shortcuts for the Show Previous Tab and Show Next Tab actions, the option key is not applied.

In the screenshot, you can see—through

However, when you will use those keyboard shortcuts in Xcode, you will see a weird behavior where the tab you are switching to, gets opened in a new editor.

This is due to the default navigation preferences of Xcode, change the "Optional Navigation" preference from "Uses Next Editor" to "Uses Tab".