You know why this whole concept repulses me? It's because it all hinges on defining Mara Jade as "Luke's wife" and nothing more.
Leaving aside all of the maybes around whether or not Luke could have or should have had a romantic relationship with anyone in this period; Mara as his romantic partner was far and away the least interesting aspect of her character. She had so much more going on than that, and to think that anyone would want all of that put aside and wasted for the sake of a meaningless cameo is baffling.
If they're going to do Mara Jade in live action canon (news flash; they're almost certainly not), then I'd at least hope they do her character justice.
I've mentioned this before, but I still think the ideal way to use her character is to entirely disconnect her from Luke's story, and sub in Galen Marek, with Juno Eclipse being one of her many cover identities.
That way, you get two fan EU favorites into canon for the price of one, and you get to maintain the integrity of both of their characters and stories without compromising Luke's.
Plus let's be honest; Palpatine sending an assassin after Luke in the lead up to Endor makes no sense at all. His goal would always be to recruit him to replace Vader, and by that point, he'd already broken Vader (or so he thought) to the point where the chances of them teaming against him were negligible. Now, on the other hand; Palpatine embedding one of his assassins into Vader's staff to spy on his supposedly secret apprentice, thereby staying 10 steps ahead of him is 100% a Palpatine move.