Charges failing is fine - but this should be because of too much suppression fire or too intimimidated by the enemy - not because i roll 1cm too little... Seems very 40k-random in an otherwise grownup rule set.
I always liked the way in E40k, units could advance to within charge range then get shotup enough prior to the actual combat that they failed their supression test for the charge (though not always having taken actual casulaties) Of course you had to account for this and suppress them first or if you played it well you could make a large enemy detachment waste its firepower deterring a coming assault. Of course now in EA, if a unit fails its activation it just skulks the other way and hides.
If i find a willing tinkerer i will try a playtest some time