We've had everything from S8 spoilers, to who's staying and who's leaving, to organizational structure changes.
And all the rumors in between.
I'm mainly focusing on the news about Gough and Millar, the creators of the show, leaving. I've seen people post that the network fired them because they wouldn't let Chlois happen. I've seen people post that the networks fired them because they wouldn't let Clana happen. I've seen people post that the network fired them because they wouldn't tie the last season into the mythos. I've also seen people say that TW and the cast were having conflicts with them, and also now that they are gone we'll have an even better show.
Everyone wants to justify their own position.
While there may have been instances where TW didn't like the direction of his character, or where MR didn't like how his character was portrayed, is irrelevant. We'll never truly know what the people involved think unless they tell us, and even then, you have to take everything with a grain of salt.
Usually in situations like these, the simplest answer is the right one.
SV is an aging show. As a show gets older, the expense of the show tends to outweigh the budget. Actors, crew, and writers demand higher salaries. There is the cost of special effects. The "new shiny" aspect of the show wears off and the network doesn't give it as much promotion and publicity.
Entering its eighth season, SV eats up a lot of money. It's the job of the studio to try to keep the costs and expenses down. We as fans might not like that, but that is what they do, especially if rumors are true that CW is struggling.
The most likely scenario is that Gough's and Millar's contracts were up and they could not reach an agreement. More likely than not, both Gough and Millar wanted more money and the network couldn't afford to pay it or was unwilling to pay it. The same can be said for KK, MR, and AM. While it seems KK truly wants off the show so she can pursue other interests, others like MR and AM might be more dependent on money. I'm not implying this makes them bad for wanting more – not at all. The longer you are at a job, the more you expect to make no matter what job you have. It's just standard business.
AA, ED, and LV can easily be signed on if they weren't already in a contract because they wouldn't cost as much as the actors who have been there since day one. Plus, if they were already in a contract, then there is no dispute.
The show cannot work without TW so he is priority.
Now, with all these changes in place, I still doubt that any segment of the fandom will get what they want. We still have the same writers and the same writers are still under the same monetary restraints. Just because Gough and Millar have left does not mean it's going to be the Lois and Clark show. However, since it is the last season, there is a strong possibility that both these characters will have a more intense focus. (And if Clark doesn't have the main focus, then shame on you writers.) It just makes sense based on the mythos. If MR is back in some capacity, I would see his character getting some intense focus as well.
Jimmy and Kara should also get closer to the mythos.
The objective of the last season should be to push the characters the closest as possible to their iconic forms and to close the chapter on Clark's very very very very very long Smallville life.
I would expect Lana's importance and Clana to slowly be phased out, but since this is SV I was never under the impression it would be 100% gone until the very last episode. It is my hope they will settle them into a nice friendship with whatever eps KK has left.
As for AM, since Chloe is an original character her arc is left open. They could kill her off if AM doesn't sign, write her out, or keep her open for guest appearances. If AM does sign, they can do whatever they want with her – they could give her some kind of tragic ending for the finale, show her still reporting whether at the DP or elsewhere, or find a new path altogether.
But what I expect and the reality don't always match up. It all boils down to money. Whatever SV can afford to do, they will. Whatever they can't? Well, that may be good or bad, depending on the outcome.