From a business perspective: Who would be complaining if they didnt upgrade the endgame nightfalls and weekies to the new levels? Bungie would have to deal with pissed off players who paid for an expansion had those activities not been updated. So it comes down to upgrading endgame stuff to please paying players, or leave it at low levels with year one exotics to please people who dont want to pay for an expansion and rather want free handouts. Bungivision knows not to bite the hand that feeds them. Have fun losing against Bungie.