We have developed a Worklight application using Worklight 6.1 and we have kept minimum dojo files required in it.
In Android devices, It is showing a black screen for a long time after the splash screen is shown.
Please wait for Worklight 6.1.0.1 to be released in early March (soon), which will include improvements in the area of application launch time, specifically this should enhance significantly the application first startup time.