Thank you for your overview.
I had a netclass defined in the schematic for the Ethernet MDI interface, but a few days ago, I scrapped it and switched to assigning netclasses in PCB New using regular expressions. This goes against my initial desire to have everything defined in the schematic. However, the method of defining netclasses by attaching a rectangle with the definition to each individual signal is only practical for a limited number of signals. For instance, DDR3 involves around 50 signals that must adhere to specific length and impedance requirements. In my schematic, the connection between DDR3 and the CPU occupies only one side of an A4 sheet, leaving no room for 50 rectangles. Some EDAs will allow for the netclass to be defined en masse using a single rectangle that intersects the respective signals.
I must also mention that for effective work with high-speed signals, net classes based on layer are essential due to varying widths on different layers depending on the stackup. Fortunately, this feature is set to be introduced in V8, as discussed on the KiCad forum (Net classes based on layer - #6 by glenenglish).
I experimented with a plugin for handling length matching in V6, which, to my knowledge, isn’t available for V7 yet. I haven’t fully tested its capabilities, but it appears to source lengths from the Net Inspector.
Ultimately, I believe having the electrical length displayed in the Net Inspector is crucial. With net classes based on layer expected in V8, and if a way to graphically save netclass definitions directly in the schematic and everything could somehow be connected on its own rules, it would fully meet my needs.