From Aeruyo to Malviz: A little morphology

Since my last post on deriving Malviz from my existing Malviz language, I've worked a little on the morphology of the language.  Aeruyo had a complex inflectional system on both nouns and verbs, so in order to work out the morphology of Malviz, I simply ran several fully declined nouns and several fully conjugated verbs through the sound changes to see what irregularities and mergers occurred naturally.  Then, based on this work, I made the following morphology changes:

 

  • I got rid of the vocative case.  In most cases it was merging with either nominative or instrumental, and I had planned on getting rid of it anyway, so it seemed like a good opportunity.
  • I merged the plural and collective for spirit nouns, since apocope had essentially done that for me right out of the gate.  In cases where the collective form causes o>u mutation (particularly in oral ~ uro > oral ~ urz), I kept the mutated form as the plural/collective form, though analogical flattening in some roots isn't ruled out.
  • All verbs had the non-past positive and negative forms merging, while the past forms remained distinct, so I extended the past tense negative forms to cover non-past as well (essentially creating a tenseless negative form and avoiding the need to create a negative particle.

 

There are still a few cases where forms are identical, but for the most part those are quite regular.  One issue I have with verbs is that they are merging in different and interesting ways depending on the root, which is making it hard for me to decide what forms to keep.  For instance, often the potential and optative moods are merging in both positive forms but not the negative:



Indicative Potential Subjunctive Optative Necessitive
Past khon khonrz khonm khonrz khoŋrz
Non-Past khonv khonrz khonai khonrz khoŋrz
Negative khongui khonrui khonmmoi khonzui khoŋgrui

However, there are cases where it does not merge:

Indicative Potential Subjunctive Optative Necessitive
Past adeh adez adem aderz adegrz
Non-Past adev adez adei aderz adegrz
Negative adekui aderui ademoi adezui adegrui

And there is one rare case where the necessitive also merges in with potential and optative (again, only in positive forms):

Indicative Potential Subjunctive Optative Necessitive
Past per perrz perm perrz perrz
Non-Past perv perrz peroi perrz perrz
Negative pergui perrui permoi perzui pergrui

I probably will apply some sort of analogical flattening for the last case, since it requires such a specific initial configuration (an Aeruyo verb root CVrV-), though the more common merger of potential and optative is quite interesting.  Should I just completely merge one to the other (the pronunciations are quite close, after all), or should I say, keep the distinct optative negative form for some vestigial usage?