Yes, that was my idea, a playthrough that does not involve (ab)using the most powerful combos in the game. I think that the game would have been more demanding of a player's strategy and skills if it would not present the opportunity to the player to use them, i.e, it would have been better for those to never exist.. There would have been diversity in play. Every creature should have a % chance of being attractive enough so that a player uses it. Who uses Bears? Undead Spiders? Zombies? Who ever chose Snakes, when he can buy Royal Snakes? Well I read something about using Bears for keeping armies with no-retal alive for rage and mana growth, by using their sleep mode, but I think that was for The legend only. ( i hope i did not give you any ideas :p)
I think that if you insist on having the dragon making some kind of damage, let it be Crushing Blow .. or Ball of lightning. I don't think Ball of Lightning is that good when there are multiple strong stacks, as you need time to kill them all with it.. Sure there is awaken dragon but still, you waste your castings with the hero by it. Doing massive damage with the dragon to all or almost all enemies takes out a lot from the strategy of playing with the units. (with a powerful enough dragon you could beat lethal armies or invincible with 5 stacks of peasants, dragonflies, firefly, hienas, etc.) Besides, Ball of Lightning is not so good in Gremlin fights i think, whereas with a dragon dive you can hit all gremlins and units.
The no horde quantity buy idea is to "care" for your units. I mean, think about devilfish. They are inexpensive, and Horde after a certain mission on Scarlet Wind. One can use them as a "berserk kamikaze" unit in most battles with melees. Just cast bless and stone skin on them and that's all. But to have them limited by number means you can't do that all the time because at some point you run out of them. Anyway it applyes to other units too I just wanted to exemplify.
No battles lost does not mean no reloads. You can reload all you want. Means you must not actually lose a battle and go back to the castle and continue from there. ( In the legend some players abused the fact that the hero was given free new troops when he was put at castle after a loss of a fight (retreat actually), and you could basically make legions of fearies and peasants for free. just attack a random monster and retreat.
Using a scanner would be , in my oppinion, yet another attempt to bypass some of the challanges a game presents. Knowing that everything will be perfect and easier then it should be. Why not just start a game and see how it goes. Even the worst case scenario game should be winnable by a skilled player. Why avoid the challange if challange is what you seek?
Regardless, it's up to you eventually to pick the constraints that you consider desireable.