I'm having a big game tomorrow against Daemons at 4000 points each. I'm playing magic heavy, but at this level I don't think there will be an appropriate number of dice around. Has anyone got any ideas on any modifications to make (if any). I was thinking 3D6 + chanelling, and then the dispeller gets the highest and lowest.
Yeah the big problem with the new magic system is that it really doesn't scale up very well. I'd almost give a more predictable bonus, like 2d6 + 6 or something, then +3 for the dispel dice. Otherwise it can be very very unreliable, in a turn with a 4000 point army you could wind up with only 4-5 dice, which won't give you anything. Or you could essentially split the 4000 points into 2 2k armies each and give each section of the army the normal 2d6. Your idea would also work, it really depends on how much of an influence you want magic to have in the game.
I think that the lack of scaling is intended, as it makes sense logically in fluff anyways. You are rolling to see how magic magical winds is in the area at the time, this won't increase with a larger army, just as you don't roll 1D6 at 1000 point games. Your wizards are still potent at whatever level, it just isn't an "I WIN" button to cast dwellers below or Purple Sun due to the fact that the opponent force has more models. I have heard argument that all 8th ed games should be played at 3k points or more due to this fact. The only army that would make sense to add more dice is Greenskins, due to their "waagh energy magic". I think it just needs to be accepted with the new rules that at lower points magic is ridiculously powerful and that one slann can level an entire army, but at larger point values magic is more like a special kind of siege engine; strong but limited in effect.
TBH i think this rule is missing somewhere in the larger games bit of the rules... certainly it's what we use. Keeps it nice and random, especially if different sections of the armies have different magical abilites!
To twist the rules completely, and match our opinions on fluff, normally our gaming group lets each Wizard channel once per level. Thus there's actually a reason to take more than one Wizard, plus the power balance between wizarding levels is closer to the fluff. And that means at higher points (more Wizards) there's also a bit more Magic!
For our 4vs4 game we did: 3d6 Power dice = total Dispel pool = highest + lowest Then each sides General (it was one for Order, one for Destruction) had to choose what to cast, and who was casting. Obviously we were able to try and get an arguement into why our spell should be cast.