Of course he's going to appear, especially in the final confrontation as it's his duty to protect them. Teshin is under the control of the Grineer Queens. He allied with the Sentients to kill us because his revenge is all that matters now. Stalker hates the Tenno, the Orokin are dead. Ontop of that they can but power caps on older content so we still face some resistance there even in our OPest builds. This would also come with newer and better rewards obviously so we can keep progressing endlessly. Much like GRifts in D3 or maps in PoE, where there is always another tier (although PoE maps are in effect limited) to beat. So DE needs to make a mode designed with the utmost optimal gear in mind, then have that content scale further so we can push ourselves. So what exactly is it that you want the flagship to be? I mean even if we get RJ to bind all of the game together, it still wont actually be flagship content when it comes to what you want it to fullfill, because most of the content will still be far too easy and left in the dust by power creep, thus not justifying or validating our progression. Well that doesnt help one bit since it is still up for wide interpretation. So you want what is mostly considered endgame in PvE games.

Yeah sure, you want something to justify and validate our progression. No specification of what you actually want. It is just like the 'we need difficulty!' or 'we need endgame!'. But still you fail, both in your OP and every other answer, to explain what the flagship should be in WF. Obviously it is all over the place with no actual Flagship, well it has a flagship but it doesnt serve the purpose of this type of game. And instead is trying to mutate into a fairy or something. It's about a toothbrush that's no good at brushing your teeth with.

I don't know how else to simplify it, and what kind of analogy to invoke. Right now Warframe is a Swiss Army toothbrush abomination without the actual brush. 'Flagship content' of a toothbrush is its ability to brush teeth, and the rest of the toothbrush is designed around performing that task. Or probably didn't bother to read the original post. But some people either cannot, or refuse to, or pretend not to understand. There are commenters who understood it instantly. This whole thread turned into me trying to explain what flagship content even means in the context of WF and people not understanding it.

Endless sky change flagship