Seems unbalanced if the cats, bats and rats have the same hitpoints as an untrained human. For example if my best friend punched me in the chest with his best punch naturally I'd still survive, yet the same punch would kill a cat. I would believe hitpoints to be more linked with the size of a unit since a trained human would suffer the same damage as an untrained human when struck with any amount of lightning damage.
The thing with Hit Points in this case is that they represent more then strictly durability, they actually represent; toughness (your natural ability to resist damage), evasion (your ability to avoid damage), skill/training/experience (your knowledge of combat and using it to survive longer). Its more of an abstract quality describing your overall survivability rather then a specific part of it.
Now, I would like to see training be able to do more then strictly increase a units HP, I really hope that training can also focus units into certain uses and give them special abilities. Off the top of my head lets say, Beserker Training, increases HP by 1/2 the normal amount, but also increases attack, or if there is morale, frightens the opponent making them more likely to flee. Perhaps this type of added depth/feature will only show up in an expansion, or mods, or maybe Stardock just hasn't announced it yet.
I realize it is an abstraction HOWEVER since they do have a STAT for defense, it only makes sense that ability to dodge should increase THAT stat rather than a hit point raise. You may say 6 one way, half dozen the other. I disagree though, unless the stats are completely invisible to the the player. If they are going to include a stat, then they should make it meaningful. You may say that doubling hitpoints has the same end effect of halving the chance that you get hit - not necessarily true. I pointeed out before that training should increase your Attack stat. Someone countered that with more hit points you will survive longer and therefore do more damage. More damage when? before I die? again why include the Attack attribute if it means nothing, and everthing is just going to be abstracted to base hit point increases? It makes a lot more sense that training would both raise your chance of avoiding damage (parrying, blocking, and dodging) and increase your chance to hit as well as doing more damage when you hit (knowing where to hit is a lot more important than how hard you hit, especially with a weapon).
So the argument that it is all just an abstraction and doesn't really matter - I strongly strongly STRONGLY disagree. And I think that only raising attack if you get like a magic sword or whatever is not the right way to go.
Training should increase attack and defence, with maybe a small hitpoint increase. As has been stated hitpoints should most closely relate to size. Defence should also be based on armor and agility (if that is a stat)
Also is ability to hit and damage done per attack going to be two separate attributes?
Are there going to be different damage types? It seems like in a game called elemental, it would be silly NOT to have fire, cold and poison damages to name a few....since the system will already be there, why not add crushing, piercing, and slashing? That plate armor that might protect well against a slashing or crushing weapon might not be so great against crossbow bolts or spears! Hmmm and dragon flame - can you say EZ bake oven? I knew ya could!
