He probably means permanent editing, you can give a fake nickname with Pokesav but you can't overwrite the original name (The one in capital letters). As for that, I don't think Nintendo wanted original names to ever get changed, but that's concluding without evidence and with my awful intuition.
Something I've noticed as I change the evolutionary path. Sometimes, the level goes down by 5. For example: I change Typhlosion to evolve into Ho-Oh at level 45. When it evolves, Ho-Oh is actually at level 40, regressing 5 levels. I've tested this twice, and both times the level went down by 5, but I still can't see a common problem that would cause such a symptom. I hope it's just another slight typo in code.
EDIT: The same thing happens in Platinum. It appears to happen whenever I change the evolution tree.
Inspection of the Python error log seems to be all the same message:
TypeError: updatespdef() takes exactly 2 arguments (1 given)
TypeError: updatespdef() takes exactly 2 arguments (1 given)
TypeError: updatespatk() takes exactly 2 arguments (1 given)
TypeError: updatespatk() takes exactly 2 arguments (1 given)
And it continues for every stat I update. I believe this is a mere syntax error that came from the transition from D/P/Pt to HG/SS, but I have neither the Python knowhow nor a D/P/Pt rom to test it upon. To me, it seems that the interpreter is taking one argument at a time instead of both at once, leading to the double error, but then again that's just me. The stat changes worked fine in game.
EDIT: Same issue with Platinum.