Again, mainly just from the top of my head; can't guarantee the accurateness of this "information".
Most modern Indo-European languages with a productive case system prolly have less than ten inflectional cases of nouns. Sanskrit has 7(8) of them: nominative, accusative, instrumental, dative, ablative, genitive, locative (and vocative: native grammarians consider vocative a special instance[?] of nominative). In Sanskrit the cases are called just by an ordinal number: prathamaa vibhakti, dvitiiyaa vibhakti, etc. (first case, second case...). That probably reflects the varied use of many of those cases. Calling them by functional names like "instrumental" , and stuff, gives a somewhat distorted view of their different uses. It seems like in time the case systems tend to give way to syntax that relies more on prepositions and/ or postposition to indicate the syntactic function of nouns and stuff in a sentence. For instance modern English only has one productive case left, namely possessive (= genitive). A couple of pronouns still have a separate form for objective (accusative), like 'him', 'them', 'me', 'her', 'whom'. I have a feeling that if a language has a case system like Sanskrit, Latin, Russian, German, and, from another family of languages, Finnish (15 cases) and Hungarian (18 cases?), all the elements of a noun phrase usually need to be inflected, which sometimes is rather clumsy, and feels like way redundant. As an example, adding (one of) the Sanskrit case endings, namely '-ena', for instrumental singular, into a sentence like The flow-job was given by a young beautiful blond Texan chick would result to (replacing the prepositon 'by' with '-ena'): The flow-job was given an-ena youngena beautifulena blondena texanena chickena. Instead of one 'by'-preposition one needs six '-ena'-suffixes!