I always thought Soran had the potential to be a great villain. Or tragic hero, if you like. And then factor in how you could explore what made him a refugee in the first place... If you no longer have to observe canon, then I guess you can have an even faster Enterprise on the scene when El Auria falls. A recast Soran comes up with his plan to lure those who perpetrated the destruction of his race, into the path of the Nexus ribbon. It's simply a means of getting revenge on a few Borg cubes... A destructive force of nature he plans to put to good use. Nobody over there is aware it's also an entrance to a pocket universe and potential exit to multiple others. With a fleet decimated defending the Federation from Borg invasion, Soran gets a desperate Kirk & his crew involved in this Nexus scheme... only somewhere along the way, they accidentally wind up inside it. Which is where your Shatner, McDowell, even Stewart and Goldberg cameos could all conceivably happen.