I think there should be Halo game with female lead role in future.90% of games out there have male protagonists,give woman's a chance!B.R.if you read this know that i support you with all my heart and you're awesome !<3
In the Sprint they mention that they were originally considering either Thorne or Palmer to have the place Locke had in the game.
I think its extremely unlikely for the following reasons:
1) The mainline Halo games are focused on the Chief. They can't do loads of spin off games that would detract from development of the main series and there has been nothing to suggest that they would. Without spin off games there just isn't anywhere to put a new lead character.
2) All the backlash against Palmer and as I mentioned above, the fact that they dropped her as a lead character in favor of Locke suggests that 343 believes a female lead would be alienating to what they think of as the core Halo demographic.
3) The only spin off title 343i has is Halo Wars and arguably they don't have a playable lead character at all.
4) All the Halo 5 backlash over the introduction of new characters would probably set back any plans to add a new female POV character.
However you could also argue that Cortana and Isabel ARE the lead characters of their respective series, even if neither is a player character. I know for a fact this is what 343 have said in relation to Isabel and Halo Wars; she got a lot of attention and we definitely spend more time with her than any other character. With Cortana they argue that its a dynamic duo, but then they also say that the Chief is a cypher for the player and they have sort of centered the plot around Cortana; so they arguably have made her the main character.
However if you mean a playable female protagonist, Vale for example, I don't think it will happen anytime soon. If it did, then it could only be through a shifting point of view system like in Halo 5.
I mean generally speaking FPS games don't have lead female characters, like you have in action/RPG games. I think most developers generally perceive this as being a genre mostly engaged with by young men and are generally suspicious of a female lead character.
Personally yes I would very much like to see them do it and I think attitudes towards this have noticeably shifted. I just don't think they will.