So, this is an idea I've had, that I thought I would throw out there. What if, instead of spending platinum for players to skip story quests, what if there was a new quest, that could give new players the things they did do the new content, while leaving hints at the main story so as to tempt the new players to go back and play/replay these missions.
Another thing that could make this mission even more exciting for both new players and old players is maybe having it be multiplayer compatible, that way the older players can play with the new players they invited to Warframe.
Maybe there could even be essentially new/special variants of the items that the new players need, that would also encourage older players to play the quest. Like maybe a special Necramech, that you get immediately after completing the mission. I'm not sure what other items new players need to play New War and the other newer content, but giving out newer versions of the required items in a new quest that allows new players to jump into the new content, while hinting at the older content and the rewards they entail, could be really good.
That's just my idea.