I always loved how Dark Age of Camelot handled stealth. The assassin-types hit very hard from stealth, but are also pretty squishy.
The stealth was essentially pure invisibility with regard to non-stealth characters, but other stealthers are able to see each other for decent counter-play. If they're melee glass cannons, then it's not so bad. They are good at what they do, taking out other squishy people. It's a rock, paper, scissors style.
But others have hit the key point of frustration which is CC-locking. Though that is a different issue, though they're typically coupled together.