First off, I didn't decide to try antimagic in 4e just for fun. A war against magic and magic-users was the major plot arc of the game in which I used antimagic in 4e. If the king makes it his mission to purge all magic from the land, you can bet he's got a few tricks up his sleeve to deal with spellcasters. He's not going to throw wave after wave of soldiers at the archmage in the hope that maybe some of the army will survive the fight; he's going to send in a small assassination squad that's specifically trained to break wards and resist magical assault.
Second, I never used traditional antimagic fields that block all magic. Not once. Over the entire campaign, only three specific encounters contained an antimagic specialist, and two of those couldn't stop casters from casting if they'd wanted to. I would never ever EVER run a combat entirely within an antimagic field because that's frustrating for everyone.
Starting with Monster Manual 3, Wizards drastically reduced the number of monsters with resistances, because it's no fun for a player built around fire attacks to come up against a monster that's highly resistant (or worse, immune) to fire. Instead, fire monsters have traits or abilities that activate or become more powerful when they're hit with fire. Instead of feeling useless, the player deals full damage and is faced with the tactical decision of when to use fire-based attacks.
This is the approach I was aiming for when I built my antimagic specialists. In the next few days I'll be posting the three stat blocks to give you a better idea of exactly what I mean.
