There was a dev alpha build that went out late last night. I'll try to answer most of your questions:
The proposed changes for technology are great (new techs, new units, new brigades). For most tech trees, I would suggest adding 1 tech between 1918 and 1936. I think no major country should start with 1918 Inf.
All majors now do not start with any 1918 infantry. Some do start with 1918 Great War Marine and Mountain, while other majors haven't researched any of these two.
If coding is possible, allow 2 brigades per land unit
Already on the list is to put all the unit's number of attachments allowed. It will in the misc.txt file like the naval ships. I t will require changes to the code to support multiple brigades for some units, and update the existing code to read/write to the misc.txt file.
This is needed to support the air-to-air and air to ground missiles, escort fighters for transports, air refuelers, etc.
(Mr BOnarpte) Slightly better intelligence on military numbers (secondary focus, information on various types of land units, capital ships).
He's now on the 1.13 release team. On the list is to update the Intel screen to give more detailed information.
Example of the naval section:
Instead of seeing "They have 7 Battleships, 2 Carriers, and 3 Battlecruisers, while we estimate that they have around 85 smaller ships."
Dependent upon the number of spys, intel %, etc. it would break out of the ships. So Destroyers, Heavy and Light Cruisers, Light Carrier, and Carrier. Additionally, it could also list unit's in the Production queue.
cost of HQ to enable most countries to produce a few.
Oops.

Missed that one. Fixed now.
Also reduce their range in attack to motivate major powers to build more of them
I like this one, but we'll need to discuss this among the release team.
Work on events should be limited to solving important issues. Of course, no spam of events.
Most new events are already done, but there are a few still to be made. As for the spamming of certain events (e.g. "Do you want to outlaw XXX", etc.), they now have local flags. Once the random event fires, it will not fire again for that country.
Tweaks in some parts of the map. Using a new map is way beyond our current capabilities.
I wouldn't want to do any "tweaks." Using a new map is not beyond our capabilities, it's just very time-consuming. We, the release team, have already discussed this and it's almost certain it will not be in the 1.13 release. We have discussed it being in another release.
No Cold War expansion as I feel you have more than enough work to do on other items.
Techs are needed until 1950 or 1953
We have techs going up to 1964 now.
Penalties for not spending on Military expenses - your best generals should periodically leave for the Private Sector
Closing the cheat that you can leave your military unpaid for years with only minor losses in terms of attrition.
This is something that the release team needs to discuss. I never knew that cheat, as I always keep my military funded 100%.
it would be great if troops could be loaded on to capital ships, for transport to other ports/bases only - no amphibbing without transports. 1 division/Cap ship. I believe this took place...? Yes - in this game, Naval Transport ships are both large Troopships/Converted passenger liners, and amphib landing craft. I think of it as the one being "attached" to the other.
I'm not for capital ships being able to transport troops. Transports are cheap and we now have 6 types. There will be a ship (Helicopter ships, LPHs) that will carrier a MEU (Marine Expeditionary Unit) and allowed to carry an Air Unit (Helicopter) that can attack provinces. Additionally, we have plans for new unit types with one being Converted Liners for troop transport that are quicker than normal transports but can only transport troops from one port to another (no amphibious assault). As for all of this getting into the 1.13 release, depends upon time and human resources available.
AC's were a scout vehicle, mostly, correct? They could therefore improve speed +1, as well as organization and soft attack.
Increased in speed by having an armor car? I can't see that. We now have 7 Engineers (1914-1964) to research and they increase speed from 0.35 to 2. They also increase toughness, defensiveness, suppression, and airdefence.
Below are the new technology research screens. They are not finished yet and we have plans:
- for expanding the manufacturing by adding 3 new techs before 1936 and 3 after 1940
- for expanding the assembly lines
- separate radar and ASW technologies
- adding more medical technologies
- expand the Cryptography technologies
- add computer technologies
- possibly break out the CAG into their own technology tree (still discussing)
- add 2 mining Equipment technologies
- add 2 Oil Equipment and Exploration technologies
- add 3-4 Power/Utility Generation Plants (Dams/Hydro), Coal, oil plants) technologies.
- create 11 new research types (tech team skills):
- Medical Science
- Aircraft Testing
- Vehicle Engineering
- Munitions
- Carrier Design
- Submarine Design
- Capital Ships Design
- Fighter Design
- Bomber Design
- Military Engineering
- Rotary Wing Aviation