Dairwueh has five cases,
The following treatment only deals with the use of these cases when they are not accompanied by prepositions. Prepositions basically just ignore this stuff.
Basically, all cases except the locative-instrumental sometimes are subjects, giving us the following feature: potential subject? Of course, this is a very limited feature of most cases - the accusative being subject of a few verbs, the dative likewise. Thus it is not a very strong feature; however, as for subjects go, nominatives and genitives both very frequently occur as subjects. We basically can assign those two the value +subj.
Before going on with this, I need to explain quickly the use of the genitive for subjects in Dairwueh: the genitive stems historically from an ergative case. It is used for definite subjects of transitive verbs.
Now we have (nom, gen) vs. (acc, dat, loc-instr). We want for the next feature to pick out one or more out of both these sets. Obviously the feature needs to distinguish nom from gen. Genitive and loc-instr both do adnominal things, but we can also consider how dative and genitive both imply some kind of control over something else: the dative receives control, the genitive has control. The nominative, however, also can have control over something - in the case of an indefinite subject it has control of a transitive verb, so, this particular feature would only serve to divide up the (acc,dat,loc-instr) set: (acc, loc-instr) vs. (dat) which pairs with (nom, gen) as far as this feature is concerned.
This is not even really all that ineffective, but helps us envision how to split the next pair of pairs: (nom, gen) and (loc-instr, acc). Alas, I cannot come up with any feature that would distinguish loc-instr in particular from accusative while also distinguishing genitive from nominative, except for the dialects where the locative-instrumental marks all possessums. For such dialects, a "possessor/possessum" diagonal split would work. However, this diagonal only splits the cells it passes through, not including the two other cells of the table at all.
Here's a different option:
The two tables above should suffice together to distinguish all the cases except for the nom-gen definiteness distinction. This distinction is explained above, and is unique to that pair.
This featural decomposition basically hints at how these cases are used beyond the implications their names imply: recipients, locatives and instrumentals, possessors, subjects, objects.