There's no reason for Nintendo to have a Direct other than to highlight a specific game they want to advertise. They showed us their lineup for Spring and early Summer with the last direct. Any information pertaining to the second half of the year is going to be at E3 -- which Nintendo is admittedly returning to a more traditional presence this year.
They've had those types of NDs before, I wouldn't be surprised if they focused a ND this month or April dedicated to MK8. But they could also have a short ND where they talk about eShop games and a handful of retail games with more details, who knows with Nintendo?