"vital challenges" is correct and usable in written English.
You can use it to refer to tasks or problems that have to be addressed or solved. For example: "Our company is facing several vital challenges that must be addressed in order to ensure future success."
Just a few weeks ago, Mayor Michael R. Bloomberg decided to invest some of his personal fortune in reshaping a national political debate that he complained was obsessed with superficial ideology instead of facing up to vital challenges.
The changes are designed to address the company's two most vital challenges: how to hold on to users at a time of competing, specialized social networks and how to draw more advertising dollars to please Wall Street.
Hyper-parameter optimization is one of the vital challenges in SVR models.
The search for clean and renewable sources of energy represents one of the most vital challenges facing us today.
But a superb defensive effort from the Shamrocks kept the damage to the minimum, with Paul Gillan getting in a couple of vital challenges.
Carrick's main strengths are on the ball, but he can tackle too and he made a few vital challenges against Liverpool.
That vital challenge remains unsolved.
A vital challenge from Alberto Moreno deflected Mario Gaspar's shot over after Villarreal had again looked to get in behind the Liverpool left-back.
Howard had spared Steven Naismith with a vital challenge on Arnautovic from the substitute's back-pass but his weakness at dealing with crosses into his six-yard box cost Everton once more.
Tim Howard spared the young defender with a vital challenge that doubled as an excellent pass to Baines, who strode forward before piercing the Arsenal defence with a superb pass into Lukaku.
It is a vital challenge for all mainstream parties to ensure legitimate debates about asylum and immigration, race and community relations are separated from the divisive, inflammatory exploitation of fears which the fascists seize on.
