Magikimnaz case structure

Magikimnaz is a first-generation descendent of Khangaþyagon, which has
evolved  from agglutinating to inflecting. I've been working on it
recently. Over the weekend I made significant progress on the noun system.
By writing a long story about the Empire of Yimegan (the culture that spoke
Magikimnaz) in Khanaþyagon, noting the frequency with which various noun
affixes occur, and factoring in sound changes and semantic shifts, I've
come up with the following case system.

                Singular                Plural
Nominative      --                      [(j)a:]
Accusative      [ku],[gu]               [gwu]
Genitive        [(j)uz]                 [zu:],[su:]
Dative          [(j)ak]                 [ga:],[ka:]
Adessive        [(j)ut]                 [tu:],[du:]
Inessive        [(j)ip]                 [pa:],[ba:]
Allative        [(j)&m]                 [(j)&m:&]
Instrumental    [(j)ol]                 [(j)o&l]
Vocative        [je]                    [(j)eu]

Notes
All Magikimnaz vowels have a prepalatalised allophone, which occurs word
initially and following another vowel. That's what the [(j)]'s all about.
Magikimnas has a regular sandhi called convocalisation of clusters. If a
cluster contains a liquid or nasal, the entire cluster is voiced.
Otherwise, all consonants will correspond in voicing to the first element
of the cluster. Where two forms of an ending are given, the first is the
form that will follow a vowel stem, and the second may be formed by
convocalisation.

The accusative has the secondary sense of prolative when used with a verb
of motion. This is because the accusative is derived by a semantic shift
from the Khangaþyagon topic marker -ku (a topic comment structure was used
in Khangaþyagon for reported speech and similar things. This became
accusative infinitive in Magikimnaz), and convocalisation of clusters made
this almost indistinguishable from the prolative suffix -gu.

Pete