Possible Explanations for this Fiasco

Rating: 1/10 (22 December 2017)

Below are my speculation and not actual events:
1. Kasdan's script was there as an adequate sequel to the episode 7 (of which Kasdan was a main writer) which was to provide some of the rightful answers like the background of snoke, Rey, and Kylo.
2. Disney, especially Kennedy was hurt by the negative review of episode 7 on its similarity to episode 4 and the lack of 'new elements.'
3. Rian was hired to provide this 'fresh perspective' to the series.
4. The set-up in the episode 7 was firmly there, so there was not much room for Rian to prove himself as a capable director to secure his future in the mainstream Hollywood.
5. Meanwhile, some of the fan theories actually found out the secrets (although nobody will confirm this officially).
6. Emergency meeting held: whether to stick to the original script or to revise it (It could be possible that at this point, quite much of actual shooting had already been done--maybe the reason for the poor pacing and illogical plot problems?).
7.Here, Rian got his moment. He proposed much needed 'freshness:' Episode 7 was mediocre; it was just a copy of an old episode; new audience need a fresh start.
8. First of all, let's kill Snoke to make Kylo a main villain to break episode 7's set up of new master and apprentice plot (another copy of the original). Episode 7's negative reaction will continue if we follow the old convention of trilogy. It is too late to make Kylo turn to light side and kill Snoke in episode 9. Applause!
9. Second of all, we don't need some special lineage to make a main character. It's the 21st century! Democracy! Chances for all! Let's make Rey just a common person with a sad background! That's fresh indeed! Bravo!
10. Thus, Luke should not live on through this trilogy. "The past should be killed completely for a fresh start." Let's kill him in this episode. Break the legend to give more opportunities to ordinary brave souls in the new franchise! Good idea!
11. And here Rian comes up with more ambitions: how about we making this 'fresh start' thing real? New trilogy! No more comparison to Lucas's original trilogies! OMG!
12. So, we need a bridge to legitimize this new trilogy in episode 8 (which was Rian's only shot to the so-called 'canon' story). So he came up with this Casino planet with new set-up reflecting current situation of our time on this planet Earth. Oppressed vs oppressor, have vs have-nots, war vs peace!
13. The new protagonist is this boy who happens to meet legendary heroes of the Rebellion: Fin and Rose! Let's make the ending of episode 8 with this boy!
14. Plus, we need another Han Solo for this new trilogy! How about this broker/hacker of ambiguity between good and evil! Let's cast Del Toro! He will take care of this new boy!
15. Ok, then for this new trilogy, Rebellion must be ended, too! Sure, let's mix out new trilogy ideas with episode 8! Let the rebellion become just another myth in episode 9!
16. Last problem: how we will end this trilogy? we still need episode 9! Let's call J.J. again. He safely started this trilogy, he is sure to end this safely, too! Fantastic! We finally have this 'new start' for this old franchise! Rian, just begin writing right now!
Below are some additional comments:
1. The main problem was this. In the OT, at least George Lucas had this story structure fixed for episode 5 and 6 before employing other talented directors than himself. On the contrary, in this third trilogy, it seems that there was no fixed story structure for the entire trilogy or the producers agreed to demolish one to support a new franchise idea.
2. Rian should be ashamed. There are certain movies that audience want to see for themselves even though they already know the whole story like the Lord of the Rings. It is ok to twist stories to surprise audience in his previous low-budget movies. He was really good at this surprise part and people loved it. However, in a franchise like SW, you shouldn't try that cheap trick to twist a plot just to surprise. It is even worse if your intention is just to deny all the great fan theories. Even if you decided to boldly go, you could have done it in more respectful ways. but.. oh yes, you already have your own new SW trilogy!