Anyways, as per my previous model, there are interesting quirks that seem to automatically surface when I personally take on the goal to finally account for both the mi-class/hi-class contrast in Anatolian with the durative-aorist-perfect system of Core IE dialects. I'd like to remind new readers here that my exploration is not a frivolous one since Indoeuropeanists themselves still to this day admit to their lack of a coherent model to explain everything. While my previous contrasting of eventive and non-eventive explains the use of the two sets of personal endings of the verb to an extent, there are still a few cases such as the would-be sigmatic aorist (eg. *bʰērst 'he carried (at one time)') where a term like non-eventive is totally inadequate, if not wrong altogether, but it was the closest concept I could find to explain the pattern.
So here's the slightly revised model that might better reflect the functional symmetries between the objective and subjective using a progressive/non-progressive contrast (ie. progressive here is meant to signify an action that's specifically realis present continuous while non-progressive would cover everything else). My model remains effectively the same as before, just with more descriptive labels hopefully:
The mediopassive-perfective connection
It appears that there's a symmetry between objective verbs marked with *-i (> durative, mi-class) and those unmarked by it (> aorist, past) on the one hand, and subjective verbs marked with *-r (> middle) and those without (> hi-class, perfect-stative) on the other. This implies that just as the presence or lack of *-i in the objective is determined by its progressiveness, so too in the subjective between what would later be described as middle and hi-class in Anatolian morphology. Thus for example objective *stḗu-mi 'I invoke' and *dí-deh₃-mi 'I am sharing' (progressive) would oppose *stḗu-s-m̥ 'I have invoked' and *déh₃-m̥ 'I share' (non-progressive) just as subjective *h₁és-h₂or 'I am seating myself' (progressive) would oppose *h₁és-h₂e 'I am seated' (non-progressive). In other words, rather than reconstructing a separate voice, we might simply place the middle in a different aspectual category under the subjective distinct from the *r-less "proto-perfect" and further treat it as the marked "presentive" form of the subjective.
Changes to the realis mood
Another interesting aspect of this model is the prediction that while the so-called "secondary" endings (ie. the objective non-progressive endings in this model: *-m, *-s, *-t) came to dominate the function of irrealis in the Core IE dialects, the original grammar must have allowed for both objective and subjective non-progressive endings. So presumably if *h₁i-yéh₁-n̥t 'they should go' is the optative of an objective verb like *h₁y-énti 'they go', then theoretically *ḱéi-ih₁-th₂e 'you should lie down' (rather than later *ḱéi-ih₁-s) would have originally been the optative of *ḱéi-th₂or 'you lie down'.
Further, the emergence of *-o-h₂(e) in the 1ps subjunctive (and later in the derivative thematic present of Core IE dialects) could add to this account since the specific replacement of original objective subjunctive *-o-m with a subjective marker would be due to the fact that the 1ps is the only person where speaker and subject are the same and the only person subsequently of which one's own potential actions are spoken with the utmost authority. Over time, this suppletiveness in the subjunctive would begin to merge into a single paradigm hinting at a nuance between potentiality stated with authority (marked in the subjective in the 1ps only) against potentiality stated as hearsay (marked in the objective for all other persons). It's a mind-boggling issue and I'll have to think more on this.
 As per the middle forms suggested in Sihler, New comparative grammar of Greek and Latin (1995), p.133 (see link) and in Indo-European perspectives - Studies in honour of Anna Morpurgo (2004), p.506 (see link).
 Fortson, Indo-European language and culture (2009), p.103 (see link): "The close similarity of the perfect endings to the middle endings has generated much research and controversy; precisely what the connection between them is remains unclear."
 Jay Jasanoff says something similar, that forms with *-r functioning as present indicatives once opposed the "perfect" without this ending, in Hittite and the Indo-European verb (2005), p.58 (see link).