I've read through the Quick Start Rules and they've certainly captured my attention, the mechanics largely look solid, but I have a few suggestions:
On the Combat Phase page, in the When Combat is Lost section, it refers to units that are defeated in combat but 'their Defence isn't beaten' having to withdraw 1" from the victor - what is meant by 'their Defence isn't beaten' in this instance? The only reference to 'beating' Defence I can see at the moment is in the Wounding section, and that of course is to determine casualties and who wins the combat. More to the point, what happens when a unit is both defeated in combat and their Defence is beaten? Do they automatically take a Morale check (which would make sense)?
I notice Cavalry units can ignore small obstacles, which makes sense as they can leap over them, but I would think they should also move faster than infantry - perhaps double the movement speed of an infantry unit, i.e. 12".
I trust you mean Support Heroes can prevent individual models in units within 6" from being killed by shooting or close combat attacks on the roll of a 6, rather than entire units? Because if they were able to inspire entire units to resurrect themselves, that would certainly be a miracle worthy of the most devout priest!
One additional thing I would add is that a Shieldwall should have a vulnerability to being attacked in the flank or rear - perhaps the models in a Shieldwall don't get the +1 Defence bonus against attacks coming from the flank or rear?
Thank you for your questions, I am more than happy to answer them. To make it easier to clarifiy I will number each bullet point question with numbers 1-4.
Before that however I've noticed that you may have missed the section in the Quick Start Guide in the "Things to know" section. A unit refers to a single model. There are exceptions to this however in the main book with things like artillery pieces and larger mounted units such as war elephants and chariots which depending on how they are modelled may be multiple models.
I feel I way need to amend that, It should actually say, if the unit is beaten in combat and not killed they must withdraw 1" as some units such as cavalry and heroes have multiple health points. Apart from a few special weapons in the main book such as throwing heads I have kept Morale to the Morale phase, as a poor performance in that phase can decimate an army.
In the sample army builder, an equippable item to any unit is the horse which modifies that unit's unit profile with the following statistics: +1 Health, +1 Attack and +6" to their Movement. "It looks like I need to amend that too as instead of +1 Health it states +1 wound*.
Yes the support hero saves individual models from dying.
I have expanded the Shield Formation rules in the main rulebook wich goes into declaring front facing to establish possible weak points. Also some factions have special rules such as the Viking Boar Snout that can remove all benefits of a shield formation. I will try and include a quick version of the vulnerabilities when I make the other amendments to the quick start guide. In brief, the way it would work is: "Any unit that is attacked from behind, either by ranged weapon or engaged in close combat loses the benefit of the shield formation and suffers -1 to their Defence value."
Thank you for your questions and I will make sure to amend the quick start guide as soon as I can.