It is true. The journal has a lot of useful bits in it, but they are needlessly obscured by flowery language and word choice.
In an effort to aid those that might be interested in the game, but find the rules feedback frustrating, I will try to offer my non WHQ iOS understanding of The board game.
For better or worse Games Workshop games are built around a standard D6 die. They don't generally embrace all the crazy polyhedral dice of other games. This is in fact my biggest beef with GW products as you can only do so much with the odds on six sided dice. Anyway, combat in WHQ breaks down as the following:
Making an attack compares the weapon skill of the target to that of the attacker. An even score is an even chance. This is also what the journal states. What is left out is knowing that it is a d6 system. So equal WS means a hit on a roll of 4+ on a d6 (50%). As the numbers move from neutral the odds change in a non linear progression. WS 3 hits WS 2 on a 1+, a 2 on a 3+, a 4,5,6 on a 4+, a 7,8,9 on a 5+, and a 10 on a 6.
Is this critical information? I don't know. As a test, knowing only what was in the journal, my test subject quickly grasped what would be easy or hard to hit without knowing 66% or 3+ or 17% on a six by simply looking at WS numbers.
Once a hit occurs the formula is (weapon damage + strength) - toughness= number of wounds lost. This is also in the journal but obfuscated by excessively narrative and poor word choice.
Also, as guessed, Winds of Power is a random die roll. In WHQ it is a d6. In WHQ iOS I suspect it may be something else. Still knowing GW is d6 system or from a few turns of playing the iOS game, it becomes clear that a spell that costs 2 is pretty easy to cast whereas a spell that costs 5 (healing mist) is not to be counted on. For what it is worth, and not meaning to be snarky, my test subject also figured this out pretty quickly from just the journal and playing a few rounds. A roll of a 1 in WHQ is indeed a double whammy as the wizard is neutered and a monster event occurs. The purpose, as guessed, is to slap down the motivation to sit around waiting for 5s to cast healing spells.
I hope this helps someone. I have not played the iOS version too much yet, but the board game is a gem so knowing these few basic may really help in getting to a point to see that in the digital version. The journal does need an overhaul though.