Problem with dialectics is zero predictive force and zero utility. It can be used to argue about things in hindsight nearly universally, but otherwise entirely useless.
Was that easy to come up with hindsight? Yes.
Was it hard to predict the reiteration of pro and contra arguments? Not really.
Could you use dialectic approach to predict the exact character of follow up arguments? Of course not.
To sum up, none of dialectics observations are important or in any way non-trivial if you put Hegelian grandeur aside. The only attempt to put it for a practical test (Marxist theory of social development) didn't really pan out.
As for it being trivial, to prove otherwise I observe that a lot of things, if not most things, don't follow a dialectical pattern. Most things can worsen, improve, evolve, devolve, spiral, stagnate, or change randomly. Rarely do I find a dialectical pattern in say the weather, the economy, the stock market, my hunger patterns, my mood swings, or my shoes.