I honestly don't think a story skip should be added. I think that one of Warframe's strongsuits is that it gives new players lots of space to learn the game and find enjoyment before layering cinematic story quests, which makes these quests feel more engaging and rewarding when they are finally reached, and I think a story skip in any form would undermine this.
That being said, there are a few ideas I'm gonna throw out that go beyond just "pay plat to skip", in no particular order or connection:
New mission types could be available so long as the host as them unlocked (similar to the dagath node just added). This would allow players to play with their friends who are new to the game without necessarily interrupting the flow of quests. There may be visual spoilers, but skipping the quests would have the same result.
Quest bonds: Rather than just paying plat into a vacuum to skip quests, that plat could be added to the quest rewards to incentive players to eventually return to them.
lower quest requirements: similar to how Duviri can be played right after vor's prize. Even using Duviri as the prerequisite quest instead of the New War would lower the grind time drastically. This may not be feasible for whispers in the wall, but could be done in the future.
