House rule discussion - Necron table-wide special rules

In a normal Warhammer 40,000 game some Necron units have special rules which affect the entire board - namely Writhing Worldscape, Lord of the Storms, and Solar Pulse. These rules are balanced to affect all the enemy units on a 4' X 6' game table and up to about 3,000pts. When moved onto an Apocalypse table in excess of 12' X 6' and with 10,000+pts per team these rules can become horrendously overpowered. My suggestion for this would be that any unit special rule which affects all enemies regardless of line of sight be limited to those units and models within 48" of the model with the special rule. A 48" zone around such units will still affect more area than a 4' X 6' table and prevent it from becoming too powerful relative to its cost.
As usual, comments appreciated.

That sounds fair...the only problem that i have is that i have not played against necrons and i am not sure how powerfull these abilitys are.

Well to give you some idea - Imotekh's Lord of Storms abilities strikes every unit on the table with d6 S8/AP5 hits (on the Side Armor of vehicles) on a d6 roll of 6 every turn that Night Fighting is in effect which he always enforces on the first turn and which can continue into additional turns on a d6 roll greater than the turn number.

That sounds painfull!!!

I feel that if it is just Necrons vs X it should be table wide. If it is a joined forced then it should have a 32" range from the model. Seems fair as in square footage it is the same as a 4 x 8 table.