"consequential problem" is a correct and usable phrase in written English.
It can be used to describe a problem or issue that has significant consequences or implications. Example: The country's economic policies have led to a consequential problem of rising inflation and unemployment.
Until about a year ago, Branson thought it unlikely that global warming posed consequential problems for the planet.
Their engagement makes possible continued opportunities for PhD students to acquire insights and tools from neighboring social science fields with which to apply themselves to consequential problems.
But near misses are relevant to managers at all levels in their day-to-day work, as they can also presage lesser but still consequential problems.
Subsequent efforts by other officers to mold public perceptions of the affair raised far more consequential problems, and the Independent Police Complaints Commission, a supervisory body, questioned whether a wider political agenda had been in play.
In mathematics, the P vs. NP problem has joined the list of the most profound and consequential problems, and in economics considerations of computational complexity revise predictions of economic behavior and affect the design of economic mechanisms such as auctions.
This presentation evaluates differences between radiation biomarkers of dose and risk and demonstrates the consequential problems associated with using biomarkers to do risk calculations following radiation exposures to the complex radiation environment found in deep space.
When negotiations begin, however, you would be wise to incorporate discussion of more consequential problems, to the extent possible, as a means of finding tradeoffs among the full range of topics.
Current indications suggest it will be extremely difficult for the government to increase the current level of policy ambition because of internal resistance within the Coalition – which would create consequential problems given Australia has now signed on to the global emissions reduction framework.
