I have to vehemently disagree with you. With custom packages back in M06 on ps2 you could create global packages allowing you to do intricate substitutions and even, wait for it, second team packages where you could bring in your entire backup defense or offense!!!
It isn't semantics at all, not even remotely. The ability to create the intricate substitutions packages like ( 2nd TE slot, HB3, WR flip, 2nd RT to TE1 ) and then have another package be ( Str Slot, HB2, TE3, WR2/WR3 swap ) within the very same formation is far and away and completely different than sub Joe Smoe
permanently into one specific formation.
Form subs is graduating from preschool and custom sub packages is a PHD from MIT or Harvard!!!