After a review to the legends, I think it's nice to merge what's present on the SC kb into a current layout by using "META" instead of "ALT". And "RUB OUT" will replace "BACKSPACE". Good idea!
Would you consider offering a regular "BACKSPACE" key as well? Having most of the modifiers in line with current keyboard legends makes the "RUB OUT" stand out in a way that I don't know that I love. (I'd probably feel differently if it was in the caps lock position, per the actual symbolics board.)
I'm definitely interested in the option of using RUB OUT as BACKSPACE, but seems a shame to have it be the only choice?
The problem with "RUB OUT" in "CAPS LOCK" position, IMO, are 1. the meaning doesn't fit, since just very few people would actually use this key as "RUB OUT" indeed today; 2. then there is a duplicated "BACKSPACE"(Space-Cadet keyboard doesn't have "BACKSPACE", so it doesn't have such problem).
It will become a cost issue, if more choices are provided. You know "BACKSPACE"(so was "RUBOUT" as currently it's) exists in the Modifiers kit as 2u, Non-standard kit as 1u, 1.5u, Numpad kit as 1u, and 40s kit, planck it and so on. They should use the same legend for consistency. If we decide to add a "BACKSPACE" besides "RUBOUT", it adds the cost of many keycaps into all kits, which IMO is not worthy.
It's similar situation for other replacements, e.g. replacing "ALT" with "META"(which is rarer in current keysets/keyboards IMO. Really a hard choice to made). The best act is to just have one version. We could usually rollback to the previous version to provide only normal legends "BACKSPACE" and "ALT". But do we have a good way to absorb the old legends into modern keyboard layouts? Or do you think it's the best to have all normal legends. Plus one R3 1.75u "ROB OUT" in the Modifiers kit?