Yeah BRB has to be a lock for Thor 4. 100%.
Every since they showed the champion head sculpture of his in Sakaar and then in IW named the axe Stormbreaker, it felt very much like they where going to feature him in the MCU at some point... BRB is so cool, i hope they making him very stern and serious which would perfectly balance out Thor more lighthearted version of himself.
Imo BRB should be a no "f's" given character. Serious, straight to the point, no fooling around, all business... A cyborg warrior horse who doesn't have much of a sense of humor. But not a character like Drax, not to be taken as a fool, for example... He should be very smart and much of a poker face to serve as a perfect foil for Thor, Korg, Miek, Valkyrie... And hopefully one day they can all team up for a fun adventure.
I would kind of use Sam Neil's character "Hec" from the Hunt for the Wilderpeople as a template to what the character of BRB should feel like. I also hope that BRB is an imposing figure as he should be, a tall strong build beast, kind of like Korg's size but basically a polar opposite of that type of character.
