"more difficult to tackle" is a correct and usable phrase in written English.
It is often used to express that a certain problem or task is hard or challenging to resolve. For example: "The new problem was more difficult to tackle than the last one."
There are some fears that the move to local government is making these more difficult to tackle.
The internal problem of misogyny and sexism might be more difficult to tackle, but perhaps the condemnation of sexualisation by a corporation as big as Adidas might nudge some people towards progress.
Geometric distortions are more difficult to tackle than other types of attacks.
Most industrial processes especially in the food industry are non-continuous problems (batch problems) that are more difficult to tackle with process integration techniques.
Government has found it even more difficult to tackle Internet pornographers who distribute via broadband, often from Russia or eastern Europe.
The latter one is much more difficult to tackle since now one has a quasilinear system with a quadratic growth term (vert nabla d vert ^{2}d) and a non-convex constraint (vert d vert =1).
Interestingly, Peter says he has never faced overt racism while living in the UK: for him, the stigma attached to HIV is far more pervasive and difficult to tackle.
It was simply too difficult to tackle before elections.
This problem is difficult to tackle for large.
While soil pollution is more difficult to verify and tackle than other forms of pollution, there have been frequent reports of incidents.
He believes editors are corrupting public understanding of science and making it more difficult to impose measures to tackle the emissions that are disrupting the climate.
