The Collectives were also supposed to produce based on the Population on the planet, I believe. And perhaps their unique research center, too. I do remember reading something about "splitting population between research and production" in relation to the Yor. But, I don't ever actually remember reading that the didn't
need morale... just that they didn't have any morale improvements/tech. Big difference there. In GalCiv 2 maintaining a high Morale means having a greater Population Growth. Many of the Yor tech descriptions allude to the fact that the Yor can't "reproduce" as fast or effectively as other races can, and the current low Morale of the Yor certainly does seem to support this. Also, as you noted, having basically "infinite" morale could potentially be
very hazardous to the game's balance.
Also, in the previous betas, the Yor Charging Stalk improvements where in the XML files, just never used. They also had a tag "S_RaceRequirement" of "Yor Collective". This is gone in the newest beta. This seems to be replaced with the Planetary Improvements you don't have the tech for being removed on Invasion idea (the Charging Stalk techs can't be traded or stolen, after all). (Minor question here: are these buildings also removed whenever you flip a planet?)
All three of these ideas (race req's for improvements, production based on population, and no morale for Yor) might be ideas they changed their minds on or found too difficult to implement properly. Who knows. Still, the Yor may be "unrefined", as it were. We'll see. I'm still hoping that they will get the production/research based on Population.
As for ideas for the Yor, I certainly have plenty of them!

1. Increase the Morale the charging stalks provide. Greatly, imho. Something like 15/30/45 or so. Someone, somewhere on these boards, mentioned giving the Yor "Compliance Algorithms" techs, or something like that, that provided passive morale boosts by "removing or reducing rouge units". I really like that idea.
2. This kinda struck me when I thought of the Yor having strength in numbers vibe going: Every Unique Yor building (including the Charging Stalks...) would provide +1 "food"/max pop. Charging Stalks in this case are basically "just" morale improvements. The more I think about this idea, the more and more I like it. If it doesn't get in TA, I'm certainly highly considering making a mod that does this.

3. Remove the Maintenance on the Collective improvements. I think that would go a long way in improving the Yor's poor economy, especially in the beginning.
4. Have the Yor's Planetary Invasion Tech be unique to them and give a unique Troop Module that's smaller, cheaper, and holds 750 rather than 500 troops. This unique Tech can't be traded or stolen. (The Yor currently do not get the Advanced Troop Module)
5. Make the Mini Soldiers Invasion Tactic either Yor-unique or available earlier for the Yor. Either the Yor's Planetary Invasion tech equivalent or the first Terror Drone tech could provide it.
I have a few more ideas, but I gotta save something for my aforementioned planned mod, right? (Who knows if I'll actually ever make it though, heh

)