Yes random charge range will make people think twice about how they line up their charges but at least you will know the distance and know what your odds are of making it (roughly, lol). Again, it is going to make using units in isolation alot riskier and will reward those who set up attacks on multiple fronts.
I have a feeling it's going to do more than make people think twice about charging.
Armies are going to become very standoff-ish, becoming a game of big guns and glancing guns. With a meat shield.
Take this for example.
6 leman russ.
3 basilisk
and as many platoons of men with as many heavy weapon teams as possible to fill the points.
Aegis defence line.
The line is placed in a line in front of the troops. The leman russ protect the basilisk and stay at 4" apart.
Flyer wise the aegis line can take the quad gun, and the heavy weapons teams can take multishot weapons able to glance AV12.
Troop wise if you footslog at it the russes and basilisks are going to eat your face,
Shooting at it the troops have a 2++ cover save, and the tanks are spread enough to spread glancing hits. Penetratings are still problematic.
You cannot get close enough to assault, and if you did you would be assaulting through terrain and be overwatched.
You cannot deepstrike in the formation as it's too tightly pack for your unit to land.
The solution.... you play 3rd ed. And do exactly the same tactic. With no one willing to give up ground the game becomes a game of lasting out. With a last turn grab for objectives. neither tactical nor fun to play.
This is my only fear for this ruleset. As i cannot in my head come up with a logical counter tactic, without been dangerously overextended. Reliant on luck. Or using non eldar models like the aegis landing platform to increase my own chance of survival. All of which are option i would not be willing to take with eldar.
The only way to beat that is to sneak wins with guardian jetbikes objective grabbing 5th turn and cheating a victory.
There is some sadistic bastard guard player leaping with joy writing this list out as i speak....