We had a direct not even two months ago. Also, we already have a bunch of stuff already for 2019. What more can they possibly reveal for this year that shouldn't be saved for E3?
A Direct doesnt have to include a whole bunch of huge reveals. An April Direct will mostly focus on new details for games already announced and reveals of smaller games releasing in Spring-early Summer and maybe a tease of a big game.
Let's look at the March 2018 Direct for comparison
Kirby: Star Allies
Travis Strikes Again
Dark Souls Remastered
Mario Tennis Aces
Crash Bandicoot Trilogy
South Park: Fractured But Whole
Splatoon 2 DLC
Smash Bros teaser
It was basically a bunch of late ports/remasters and updates on already announced games with Mario Tennis (June), Octopath Traveler (July) & Splatoon DLC (April/July) having the biggest focus.
An April Direct will be the same with a bunch of ports/remasters and updates on already announced games with Mario Maker (June), Fire Emblem (July) & Smash Bros DLC (April/early Summer) being the main focus.
When the herd loses its way, the shepard must kill the bull that leads them astray.