Shouldn't a discussion have at least been considered over all stakeholders and not just a subset.

Shouldn't all stakeholders have an input earlier in the cycle to avoid costly decisions having to be made?

Yes and yes, and that has been the case, starting several months ago when the SPS was proposed and discussed, and in numerous ongoing discussions since. So, if you are asking whether input from non-witnesses and developers is a part of this process and is directly considered, then I would say yes. If you are suggesting that all stakeholders and platform users are directly and personally involved with the development and collaborative discussions supporting development on a day to day basis, I would say no, that is not practical (and indeed is the very reason why Steem, and most current DPoS blockchains, was designed with a modestly-sized witness set: there is a limit to the number of people who can constructively have personal involvement in such a process without everything becoming too unwieldy; at a technical level it would work to have not a top 20 but a top 200 or even more, but from a practical standpoint when the network is seen as something evolving, that is impractical).

Is this discussion onerous to you, a hassle? Then let us agree to disagree. I am happy to move on. I have stated what I think which I believe I am free to do. You have stated what you think which is indeed also your right.

It isn't extreme, but it is still a meaningful added time commitment for those witnesses who choose to engage personally in these discussions with the community (this particular one only being an example, I'm not calling it out as a specific concern). Those that don't are criticized for being out of touch and not engaging. I can understand and see the merits of both approaches, particularly when witnesses are being paid about as much as a fast food worker (or maybe, given that the Steem price has recovered a bit recently, a fast food manager), before expenses, and then are accused of using their position to do "unfair" things to in order to protect their pay check.

A proposal could have been made to all stakeholders. A for and against.

That is exactly what is being done. The process of on-chain governance allows all stakeholders to have a say for or against approval/activation of forks.

Do the views of non developer, non witness stakeholders not count. Or do they count at a later stage when the code has been written and as I said before it becomes far more expensive to change.

Disagree, as stated above. A wide range of views from non-developers and non-witnesses have absolutely been heard and taken into account earlier in the process starting months ago, including on the matter of how and how much (and if) SPS should be funded. Ultimately witnesses and developers make a practical call to distill that down to what concrete implementation they think is best for Steem. They/we may well get some things wrong but we consider all sorts of input and do our best.