So im dont really wanted to wrote it but im just had to.
1. The new system as a permanent replacement for alert is bad.
Why? Not becouse you have to complete with a friend.. its bad becouse lock out new players who cant complete 66% of the challanges.
2. The nightwave as overall a good addition (but not as replacement).
Why? No rng reward from the shop buy what you need it. And the tiers has some good and exclusive reward that the vet players wanted a long time ago.
As I see a solution to replace alert and to keep up some exlusiviti for the players who grind hard for the items, is that you put the exclusive items to the end sigil,syadana,armor,etc and more wolf cred for the beginning. Do not remove the time limit, but make it that way its only for the exclusive items after that leave the old reward alone and let the players complete them as they want (even can put in more challange to let them complete fsster). When the new one come if you didnt finish you can do it simultaneusly. So wolf cred at the beginning for the new players. At middle the rewards like slot and catalysts, and at the end the time limited exclusive items for the hardcore players.