Some people say you have to keep Paladins/Inquisitors in your ranks for No-Loss, IMHO that is not necessary (but it helps). I have done no-loss (albeit on Normal) with a Warrior using an all-Lizardman army. Resurrection for level 1-4 units and time back for my Tirexes. In the Legend, I modded the (useless) Last hero spell into an "Animated Dead" spell, that resurrects Undead the same way as Resurrection - and did no-loss with an all-Undead army.
I like playing no-loss, it is challenging, and frankly, it has been a hobby of mine since like, forever. I even played games like HOMMIII and Blitzkrieg this way (granted I grudgingly accepted loosing infantry in the latter, and in HOMM could only do this with expert Earth magic and Resurrection). I feel like a good commander at times like this, who looks after his troops.
Fatt Shade has a point though - I wish the AI would take advantage of some spells. In The Legend, there weren't many enemies that used Phantom, but it was major fun simply dispelling their phantoms... The enemy should use that and Exorcism more often.