Lets see if I have this right. To figure a To Hit Modifier, I need to first measure the distance, than figure if the distance is "short range or Long Range", then goto the hit modifiers table and figure this out?

Do all games need to use the Modifiers, or can the game be balanced without?

WOW

To-hit modifers are listed on a chart for easy reference. Shooting can be simplified if you remember that a BS 3 unit hits on 50/50 before modifiers. Just add or subtract as you move up or down from there. Modifiers can get complicated, it is a matter of knowing what your troops can do. The Wood Elf Glade Guard for example has a range of 30, suffers no modifiers for moving and shooting and shoots at str 4 at close range.
The most common modifiers are long range, moving and shooting, skirmished/single mansized model, multishot, hard cover and soft cover. with the exception of hard cover, they are all a modifier of 1, hard cover is 2. Well, these days large target is in there a lot, but it is a plus to your roll instead of a minus.
As an example, a Wood Elf Glade guard shooting at a dragon at long range would hit on a 3+ even if they move and shoot. +1 for large target, no cover, -1 for long range and their BS is 4, they don't have a multishot option. High Elf archers in the same situation would hit on a 4+ if they move because they don't get the Wood Elf ability to move and shoot without modifiers and they are the same BS. Hope it helped.