what other areas could have become "cradles of civilization" and why?
It depends on the initial starting conditions. Historically, agriculture emerged independently in several locations: the Fertile Crescent, the Indus valley, China, and Mesoamerica. The problem with choosing another area is it raises questions, like 'Are you proposing that the crops that enabled agriculture somehow appeared in other regions of the world?'
If yes, that's likely a geological PoD which may need to happen as far back as the last Ice Age. If no, then one wonders how those regions would work as a cradle of civilisation. For example, if I were to pick Morocco as a cradle of civilisation, there are a number of problems: it's far away from the Fertile Crescent (where wheat first evolved, which is a key requirement for agriculture), and is relatively isolated from other cultures by geography, which is a disadvantage because a high mix of different cultures helps the spread of new ideas. Although other cradles of civilisation had different crops (rice in China, maize in Mesoamerica, wheat and lentils in the Indus), I'm not sure there is any special kind of crop in any other part of the world that could form the basis of an agricultural civilisation.
Perhaps the Rhine could function as the basis of an early civilisation, although I'm not sure the weather is favourable enough to spur the development of an early culture, given it's so far north.
Part of the success of the Fertile Crescent is that the area is geographically important as the "bridge" between Africa and Eurasia, which has allowed it to retain a greater amount of biodiversity than either Europe or North Africa, where climate changes during the Ice Age led to repeated extinction events when ecosystems became squeezed against the waters of the Mediterranean Sea. The Saharan pump theory posits that this Middle Eastern land bridge was extremely important to the modern distribution of Old World flora and fauna, including the spread of humanity.
The area has borne the brunt of the tectonic divergence between the African and Arabian plates and the converging Arabian and Eurasian plates, which has made the region a very diverse zone of high snow-covered mountains.
The Fertile Crescent had many diverse climates, and major climatic changes encouraged the evolution of many "r" type annual plants, which produce more edible seeds than "K" type perennial plants. The region's dramatic variety in elevation gave rise to many species of edible plants for early experiments in cultivation. Most importantly, the Fertile Crescent was home to the eight Neolithic founder crops important in early agriculture (i.e., wild progenitors to emmer wheat, einkorn, barley, flax, chick pea, pea, lentil, bitter vetch), and four of the five most important species of domesticated animals—cows, goats, sheep, and pigs; the fifth species, the horse, lived nearby. The Fertile Crescent flora comprises a high percentage of plants that can self-pollinate, but may also be cross-pollinated. These plants, called "selfers", were one of the geographical advantages of the area because they did not depend on other plants for reproduction.