Before I start, I would like to put a disclaimer out that I am in no way a developer or understand how a game is built. Nor am I a story/quest writer. And if this suggestion had been made in the past, I apologize for presenting the same idea once again.
Now, with the recent hoo-hah about partners leaving and the on-going rant of content draught, and the defense of the content draught comparing other games to Warframe as to what content is, I personally feel that it is not that Warframe is lacking content, but the model of how Warframe is presented that is lacking. I hope we can agree that Warframe is a grindy game, it was designed to be grindy, and it should be grindy. Let's ignore the rewards part for the entire conversation. Warframe is meant to be a grind. Therefore, we can learn from one of the most grindy, repetitive game there is out there, which people are using to defend content draught, Pokemon. It is undoubtedly one of the highest-grossing, longest-running game franchise in existence.
Some have used it to counter the lack of content in Warframe and they are not wrong. DE coming up with new warframes and weapon and the like are content. Props to them for coming up with new ideas for weapons and warframes and game modes. But I think that there is a flaw with the comparison of Pokemon to Warframe: how these content are being presented, the model.
How can Pokemon, a game that has remained the same ever since the first generation came out still sell and still be popular? Literally, every game of the subsequent generation is the same as the previous one. You go catch Pokemon, beat gym leaders, and become the Pokemon League champion. That's all there is to it. I might be wrong and might have overlooked a few things, but I think that it is the way the content are being presented by the Pokemon franchise:
1. You start from scratch every time.
2. You get new Pokemon (maybe some previous ones carried over).
3. You get a new storyline (sort of). Albeit with the same goal.
If we were to use how new content is being presented to us in Warframe and apply it to the Pokemon games, it would be a train wreck.
We will still be playing Pokemon Red/Blue/Yellow, after eight generations of Pokemon (content) and we're still playing the same storyline, as Red (protaganist). It is no wonder we feel that there is no reward with new content. Because our first generation Pokemon from Red/Blue/Yellow has reached Lv100 and we have a fully optimized team that could take on whatever the game throws at us. Catching new Pokemon becomes a chore and only for the sake of completing the Pokedex. They are no longer content in our eyes, but merely more grind. Having more generations of Pokemon (content) no longer feels rewarding. A new set of gym leaders to beat is going to be another same old same old thing again after a while because we can just wipe them out with our fully optimized team and the same goes for the new Pokemon League, even if they require different ways to beat (new game modes).
So what is the difference between Pokemon and Warframe? It is the model in which new content and games modes are presented. What if we take the model from the Pokemon franchise and apply it to Warframe.
Perhaps Warframe 2 is a little bit too much to ask for and I doubt veterans would want to start a new game that they have mastered. My suggestion here is galaxies. Warframe: Milky Way (the current Warframe) (first generation Pokemon) officially ends with The War Within. Plains of Eidolon is the endgame, the final hurdle. Revenant is the last obtainable warframe. Anything after that will be available in the next galaxy, Andromeda (second generation).
Now here's what's different. Somehow by some series of events, we end up in Andromeda. We start Andromeda by choosing one of three new warframes and a set of new weapons. We have a whole new star chart to clear, new warframes and weapons to farm. But we are not able to access our previously own warframes and weapons. Let's leave the minor details like essential mods aside for now. It could be solved with some storyline allowing us to obtain them somehow. All warframes and weapons after Revenant are only available in Andromeda. Fortuna is only available in Andromeda. Disruption is only available in Andromeda. There are only so many warframes and weapons in that galaxy. And when the storyline for Andromeda ends, it connects back to Milky Way and allows us full access to all our gear once again. What if we find out that the Tenno is not a mistake? Something we wouldn't have found out if we didn't end up in Andromeda? What if Empyrean is a technology of a different colony of Tenno that made it to Andromeda? It opens up possibilities, freshness, a sense of wonder.
What this does is it makes us actually feel like we are playing new content. Almost everything is new to us. New planets to explore. New enemies. New game modes that are only available in that galaxy. New warframes and weapons to obtain that are a part of the story that is connected to that particular galaxy. Churning out more warframes and weapons is basically redundant right now because we are not experiencing a sense of new-ness. It's the same old same old.
I understand that Warframe was never meant to be an epic RPG. But the current story is just a bundle of mess. Who even is the Lotus? The Second Dream is one of the best gaming experience anyone can have. I remember reading comments of veterans back then of how emotional they were, how it changed their view of the game, how it changes everything. I remember myself going, "Wtf? You've got to be kidding me!" It got me hooked on Warframe for the next 1000 or so hours. But now I don't even now what's going on.
With this model I'm suggesting, new players will not feel overwhelmed because they can choose to start in Andromeda. They can play as a Tenno in the new colony and once they finish the star chart they meet a Tenno from Milky Way that leads them there which they will start with starter frames again. They don't need to play Milky Way if they don't want to. Of course, there are disconnection that you would've thought of between the two galaxies (storyline, quests, etc.), but a well-written story would connect these missing pieces and we leave that to DE. And for the veterans, it's like a new game again. And if they like, they can go back go to Andromeda with the frames from Milky Way and optimize the gameplay there, or use equipment from Andromeda in Milky Way. Weapons types or gimmicks can also be tweaked for the specific galaxy. Maybe a new weapon element or two.
I have not farmed every frame or weapons available and to be honest, I don't feel like it. Saryn Prime is out now, I don't have it nor do I have Saryn but I don't feel like farming it. Because I don't need it. Yeah, it's meta for ESO and clearing maps quickly, but I don't need it. I can use other frames. I'm bored of running the same missions again and again and cracking relics again and again. There is no incentive to do it. But if it's a new galaxy, a new setting where I don't have the optimized frames I now have and Saryn Prime is a new frame (for example), I would have the motivation to farm for it. Because I have limited frames and need to get all I can for optimization.
I understand that there are flaws and missing joints in the model I suggest but my main point is that a change of how new content is presented would potentially be the answer to the balance between beginner/casual player content and veteran/endgame content. This requires a great amount of resources. From story writing to coding a new galaxy. I leave it up to DE to consider this model. I hope this would help point DE in the right direction for the game. It's one thing for a game to be great, it's another thing for a game to remain great.