The problem at the moment is that stealth attacks can very much backfire, you just don't see it often. The only example I can really think of is the spider matriarch. Either you fire one attack and all spiders get a free turn, or she's surprised.
-2 does essentially nothing to these enemies. I'm assuming surprise attacks exist so there's a chance to get the drop on any enemy. If such an enemy is surprised, it would be enough to enter combat automatically, but have the rest of your party attack once first before the enemy gets their turn. You're skipping the roll and have some extra time to get into position. That seems rather default for video games.
