That's a bit of a tortured example: Boba Fett was highly popular, a named character, and was featured in literature and promotional materials. Mass Effect has no character remotely as iconic or well established as Boba Fett, much less a side character, much less "a different angle".

Star Was illustrates my point quite nicely: after a couple decades of world building they're already plumbing diminishing returns in one of the worlds largest and most popular IPs only one or two stories removed from their main narrative. I have high hopes for the Han Solo prequel, but Disney isn't putting money behind "alternative" Star Wars narratives until the nostalgia well is tapped, and even then they're going full-court on a trilogy.