I think the thing that people tend to miss is that there are real limits, practical, and financial to the differences between SWTOR at release and SWTOR during the expansion period.
1) Before release, the creative teams were as large as they were ever going to get. Probably a team for each starting planet and teams for class-story, etc.
2) They had lots of time. Perhaps five years, or more. The budget was as big as it was ever going to get -- to pay for all of that (and so. much. more, not even remotely related to story, or creative).
Post-release, expansion content tightened storywise to include two stories (essentially). One per faction. After Rise of the Hutt Cartel an alternative was tried that gave one story for both factions with a single class-based quest for each of the eight.
When the Eternal Throne was released we have, essentially, one story and I think it all comes down to (s) the size of the teams, and (2) the amount of money they can budget for an expansion, given sub rates, cartel coins, and purchased expansion retail costs.
I know this is an uncomfortable subject for most people, but a realistic understanding of how a business works, (especially when operating under an external license) is crucial.
This is why players like the OP ask for/demand more two-faction content and why players like myself have 30+ alts (and usually only stick around for 3-6 months at a time with a year or more "off" in between:
Eight individual stories with light and dark side options (and I would argue, to a tiny extent -- "grey" options, if only between the ears of the imaginative player) funneled into a single overarching story. Because it was easier. And cheaper. And inevitable.
Now Q regs, kk thx.