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Paladins with Ring of Immortality and AoE resurrection (It sure is fun to suddenly find out you're surrounded by 5 enemies instead of 1 paladin or to find out all your enemies are immortal).
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Dwarves with all kinds of traps protecting their already strong turrets/barriers etc (flying in the air in middle of tesla poles, aww yeah!)
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Sister of Fire can surely turn the tables with Heavenly Fire (aka Skyfire). If orc gets too close --> Shockwave and take distance (while spamming "request help" button).
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Inquisitor can almost always choose whether to fight, or to leave. They also have Eye of the wolf ability to hunt down those poor enemies with low hp. So it's a decision between "quaranteed" kill, or little risky choice, which you can 95% of the times leave anyway if things are getting too hard for you.
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Ice Witch AoE freeze, Black Ice, Insta freeze... If an orc can catch you, maybe you should consider changing class?
Orcs may have "cakewalk" -times at lower levels, just keep going further with those levels and you'll find out that other classes are heck strong also.
Ability to turn whole team into a bunch of snowen, staying frozen 10+ seconds, just waiting for those xp hungry hyenas to turn you into a pile of ice cubes? You damn sure should get interrupted!
Sappers can't interrupt you before lv. 10 when they get steamhammer, which takes some time to build (correct me if I missed something).
Like I said, that's how it's supposed to be. All it takes is some practising and good timing.