Karl Urban stars opposite the current Thor, Chris Hemsworth, in Thor: Ragnarok, but he is backing the idea of a female Thor taking over as the MCU moves forward. Hemsworth is about to launch the end of his Thor trilogy, and will do so in a very different way than it began. Instead of the Shakespearean approach of the first films, director Taika Waititi worked with Hemsworth and the studio to bring a new look and tone to the franchise for Ragnarok. Based on the early reviews, it appears the change will work to great effect as this trilogy comes to a close.
While there is no indication that Thor is going anywhere - especially considering Hemsworth has appearances in Avengers: Infinity War and Untitled Avengers lined up - what future the character holds is absolutely a mystery. Audiences love Hemsworth in the role, but should Marvel Studios look for a new direction, Karl Urban is a fan of getting female Thor.
Related: Where Is Lady Sif in Thor: Ragnarok?
Monkeys Fighting Robots spoke to Urban during the press tour for Ragnarok and asked him about the potential of getting female Thor in the future. Urban admitted he is not familiar with the comics so he has no knowledge about the potential storylines that such a change could bring, but he says it is a move that is overdue.
I think it's time. I think it's well overdue, absolutely. I'd like to see that movie, why not.
In the comics, Jane Foster took on the mantle once Thor Odinson was found to no longer be worthy of wielding Mjolnir. The heroic turn was an exciting one for the character to make, especially as she has battled cancer during her tenure. If Marvel does go down this path, it would mark a big return for Natalie Portman, or signal the studio recasting the role. Portman has previously stated that she was done with the MCU but then appeared to be open to a return. Ragnarok will explain why Thor and Jane are on a break, so it looks as though Jane is not in the studios' plans, unless they're just keeping her out of sight for a big return.
That all said, Jane Foster may not be the only candidate to take over. Tessa Thompson's Valkyrie is being set up to be a potentially major character in Ragnarok, and is even someone that may intimidate Thor. If he was to die in Infinity War, it would not be crazy to think Valkyrie could be deemed worthy to carry on. As a matter of fact, her becoming the "new Thor" could give the studio further reason to pair her up with several other MCU heroines in their own movie.
Source: Monkeys Fighting Robots