There's a pretty interesting thread over on warseer discussing what people would and wouldn't like to see changed in 8th edition.
One of the phases that people have focussed on is magic.
It is not a problem that has an easy solution, but it is a problem.
True in most fantasy fiction there is a mage who is capable of pulling off huge feats due to magical power - and therefore Warhammer has to reflect that in some way. The only problem here is that in these fictional scenarios, this magical feat generally only happens once, yet in Warhammer it happens turn after turn. Ok there is the miscast table, but let's be honest how many players have seen this do anything significant? The mage may take a wound, but all this achieves generally is to reinforce the bunker mentally of the mage.
The main problem with the magic phase is that it distorts the game - ok you can argue that ItP does too - because it forces players to at least take part in the magic power game, and in turn makes players take mages.
Which raises the fluff question of whether or not the Warhammer world really is so full of magic users? And more to the point if the magic users that populate the world, really are as powerful as those that appear on the table?
After all if that is the case, then how come the army books and novels are mainly about warriors?
Let's face it if the fluff were reflective of the game, then very few arriors would last more than one battle in the face of strong magic, let alone lead an incursion of chaos, a might Waargh, or the defence of an Empire city. And more to the point why would people follow a warrior, when anyone with eyes can see the mage is more potent and liable to live.
Which raises the question of how to make magic more reflective of the power level of the other game phases.
Perhaps a simplification of the miscast table along the lines of the misfire table. Or perhaps making all doubles miscasts - meaning that the big spells are harder to get off - and the speels being subject to the kind of drift artillery is subject to, meaning that spells might actually miss their intended target *gasp*. Or perhpas rolling for spells each turn to reflect the way in which the winds of magic are changing, with a chance that the mage is not able to access the power.
Though a simpler solution would be to change the targetting requirement to make bunkering characters less of an option. Or allowing a free hit against characters refusing challenges, which would affect mages more than warriors, and favour players who out-manouvred the enemy and managed to track a mage in combat.
Obvioulsy the problem for the game designers is that they have to keep magic a part of the game, so it's a subtle balancing act they have on their hands.