I am working on an a posteriori Slavic conlang at the moment and while I want it to not be very unique and outstanding, I thought about is merging the nominative and accusative cases into one, as male and neuter nouns are already the same in those cases (save animate nouns) and the adjectives also take the same suffixes in both cases a lot.
The thing is, that the accusative is different from the nominative in feminine hard a-stems (plural form are the same in every stem (and gender)), which are the majority of feminine nouns. Instead, the accusative shares the same suffix with the genitive (just like animate male nouns). But on the other hand, two other female declensions have the nominative and the accusative with the same suffix. The female r-stems (only two nouns, meaning "mother" and "daughter") have a distinct nominative, accusative and genitive, but the genitive and accusative are very similar so they could merge. Here is a table with every major declension:
I also have one with the adjective declension for reference:
The masculine and feminine plural accusative are the same concerning the adjectives but I can see masc. acc. -ʲa merging with the nominative to avoid confusion with the feminine and anological to every other plural declension in which nominative and accusative are the same. On the other hand, it feels unnatural as the accusative is the most often used case? But then, the neighbouring language is Romanian with its Nom-Acc/Dat-Gen distinction so it could be influenced by that?
So I have two questions now:
1. Do you think it would be likely/natural for the language to merge those two cases?
2. The feminine hard a-stems and r-stems distinguish nominative and accusative-genitive, the soft a-stem is a mess so far and the feminine u-stems and i-stems distinguish nominative-accusative and genitive. This resembles the Slavic inanimate/animate distinction in male nouns. With the two very common r-stems ("mother" and "daughter") being animate nouns, do you think it would be likely/natural for this language to develop an inanimate/animate distinction in female nouns as well?
It's a lot but I would be very thankful if someone could help me with this!