Well I wouldn't say it's redundant, it's just not compatible with the new Interface Designer because it overwrites the position that now can't be controlled directly via mouse / key shortcuts which is like the biggest workflow enhancement of the Interface Designer IMHO.
If you choose to not bother about it and create everything with a script, you can still use the
Content.addStuff methods, but again, you miss many things.
I agree that your approach of calling the functions once, then replace it with Content.getComponent() is not very efficient. However if you start the interface from scratch you don't ever need to call one of these functions because you can create and rename the widgets directly via context menu in the interface designer (either by right clicking on the canvas or on one of the items in the widget list). So basically the recommended workflow now is:
Create all widgets using the interface designer, shuffle them around and set its properties, connect it to modules etc. without having to touch the script editor once.
As soon as you want to implement custom behaviour, customise a Panel or implement some complicated GUI logic, grab a reference to the widget (this can also be done by selecting it and pressing Ctrl+C, it will copy the line
Content.getComponent(name)to the clipboard) and use this to add the code you need.
If you take a step back, this procedure is starting to become similar to the way how you connect modules with a script (just grab a reference and do something with it instead of create it completely from scratch).