The crucial question is how we want to value the creation of new sentience (aka population ethics). It has been proven impossible to come up with intuitive solutions to it, i.e. solutions that fit some seemingly very conservative adequacy conditions.

The view you outline as an alternative to total hedonistic utilitarianism is often left underdetermined, which hides some underlying difficulties.

In Practical Ethics, Peter Singer advocated a position he called "prior-existence preference utilitarianism". He considered it wrong to kill existing people, but not wrong to not create new people as long as their lives would be worth living. This position is awkward because it leaves you no way of saying that a very happy life (one where almost all preferences are going to be fulfilled) is better than a merely decent life that is worth living. If it were better, and if the latter is equal to non-creation, then denying that the creation of the former life is preferable over non-existence would lead to intransitivity.

If I prefer, but only to a very tiny degree, having a child with a decent life over having one with an awesome life, would it be better if I had the child with the decent life?

In addition, nearly everyone would consider it bad to create lives that are miserable. But if the good parts of a decent life can make up for the bad parts in it, why doesn't a life consisting solely of good parts constitute something that is important to create? (This point applies most forcefully for those who adhere to a reductionist/dissolved view on personal identity.)

One way out of the dilemma is what Singer called the "moral ledger model of preferences". He proposed an analogy between preferences and debts. It is good if existing debts are paid, but there is nothing good about creating new debts just so they can be paid later. In fact, debts are potentially bad because they may remain unfulfilled, so all things being equal, we should try to avoid making debts. The creation of new sentience (in form of "preference-bundles" or newly created utility functions) would, according to this view, be at most neutral (if all the preferences will be perfectly fulfilled), and otherwise negative to the extent that preferences get frustrated.

Singer himself rejected this view because it would imply voluntary human extinction being a good outcome. However, something about the "prior-existence" alternative he offered seems obviously flawed, which is arguably a much bigger problem than something being counterintuitive.