Agents and patients

I'm developing a new language for an RPG setting
(Wamen and G'amah were for this one too). I thought
of having agent/patient, with a twist regarding
perception and non-volitional verbs.

The usual pattern is subject-AGT, object-PAT; but
for these verbs one might have subject-PAT, object-ABL
(ablative):

    3p.PAT house.ABL see
    'They see a house.' (*'To them from a house is seen.'?)

I don't know if this is likely to happen in a natlang.
I know Tokana has a lot of possible cases for subjects,
for example, dative for perception verbs, which is somewhat
common patten. But this is quite different... The case names
are maybe misleading (also see below).

What I'm not sure about here is what to do with the
verb -- agreement would be marked in this language, but
I'm not sure with which part of the sentence... Passive
voice is also a concern here; I may leave the verb as it
is, and change the cases again to focus on the house:

    house.ABL 3p.DAT see.(PASSIVE?)
    'A house is seen by them.'

I only have AGT, PAT, ABL and DAT, and I'm somehow seeing
a hierarchy -- in that order. Does this make sense? Any
problems with this mad scheme? (As for ambiguity: I can
live with it, plus I have adpositions to enhance the broad
meaning of the cases, if needed.) Help of any kind would
be appreciated.


--Pablo Flores
  http://www.geocities.com/pablo-david/index.html
  http://www.geocities.com/pablo-david/draseleq.html