The problem is that for any rule you come up with there are cases where that rule is just too rigid and too inflexible.
There are times where early return makes a ton of sense. Usually that's the case when you can derive the return value from a shallow interpretation of some input values (i.e. check preconditions) but still require more complex processing for other input values. In that case, return early, but constrain the rest of the method to one return point.
On the flip-side, there are cases where an early return makes it incredibly hard to reason about the function. This usually occurs in dense, nested conditional logic. In those cases, I found sticking to rule that a return value should be initialized once and only once, and return from a single point, beneficial in even reasoning about the problem.
There are times where early return makes a ton of sense. Usually that's the case when you can derive the return value from a shallow interpretation of some input values (i.e. check preconditions) but still require more complex processing for other input values. In that case, return early, but constrain the rest of the method to one return point.
On the flip-side, there are cases where an early return makes it incredibly hard to reason about the function. This usually occurs in dense, nested conditional logic. In those cases, I found sticking to rule that a return value should be initialized once and only once, and return from a single point, beneficial in even reasoning about the problem.