Ok, so I finished the SI story, and basically what I noticed;
1) It needs more credit, the sith inquisitor story actually starts off with you starting as a slave and then working your way to power by leaving a bunch of dead bodies behind, and alot of those bodies are Sith and there is you making preparations to bring down your rivals.
Eg, you are aware of the betrayals through a close source of information and you start making preparations to bring down those enemies by going along with their plans. So in effect, yes you do actually care about said ritual if you think about the plot line on more than a 'kill things' level.
2) The raw physical power of the Sith Warrior is great fun, especially as a marauder BUT the Sith Inquisitor and Jedi Consular Stories are the two main stories that reveal alot of lore, history and force secrets, IF you pay attention.
The sith inquisitor gains a) the ability to enslave ghosts, b) a title for that c) becomes a dark council member, it's one of the only few stories that show that much council time, the warrior only had council time at the end of chapter three, ok now you are not a policy maker like Frank Underwood in House of Cards, BUT it's a PVP/PVE based MMORPG, of course it isn't going to be like that. But, I felt it was the story that besides JC, held the most political themes, it really captured the selfishness of the sith council, apart from the IA story chapter one.
3) I out levelled my entire story (it's my method) I stop touching the story after Coruscant/Dromund Kaas, so I can solely focus on the story after I've reached a certain level. Once I started doing that, I found the story much more enjoyable because I didn't have to grind and try to keep rembering what happened
. I give it a solid 7/10.