Yeah, if the arguement for fully modular is that it's easier when swapping, I would say that it's only easier in one specific instance: like for like, for example in the case of a warranty replacement.
Anything else, you're asking for trouble without having to do extra research. At least in Corsair's case it does look like they stay consistent within a single product line even if they have two different manufacturers making them...
...except not always. The HX line, for example, has one type of 24-pin for the platinum rated, and a different one for the Gold. The TX-M uses a different PCIe cable for the Gold than they do for the Bronze.
I feel like it's like walking across a bridge where there is a waiting line to cross, or skipping the line to walk across that same bridge on the railing. Sure, the destination is the same, and you might get there quicker with the 2nd way and if you have all your safety bases covered and you've done your research on that bridge, you could absolutely be fine...but it just doesn't seem worth it *to me*.
Now...all that being said, that's all just in response to the reasoning to defend a fully-modular because it's 'easier' to leave cables in place.
I actually *bought* a fully modular, because I knew i was going to add sleeved extensions and didn't want to deal with having to manage the extra slack in an already-tight case with a glass side panel.