Just because you can't take on infinite five year olds doesn't mean that you will lose to a five year old.Elennsar, you've said that you wanted fairly realistic combat, but now you want every opponent to be a threat? It seems you want characters to be wary even around 5 year olds, but really, where will it all end? Is a human infant a threat? A bunny? A fly?
Last time I checked, five year olds weren't opponents either.
Not-so-well-organized spearmen, on the other hand, are opponents and are a threat if not addressed properly - even if they're much less able than you.
1) Legolas will probably be missed by the orc (high AC).And seriously, people just went over this with you. In D&D, Legolas doesn't "ignore" the orc, he chooses to defend against the orc instead of taking it out first. Combat isn't a frickin passive activity in D&D, the system just assumes that your character isn't being a complete idiot.
2) If he isn't missed in that sense, he's probably still "missed" by the orc because of high hit points.
That doesn't encourage DOING anything to deal with the orc, that encourages ignoring him.
He's not even a distraction in D&D. Despite the fact he's waving a sword in your face, you can go on your business as if he wasn't there.
You can claim the character is dodging and evading and whatever until the internet dies, but there's no visible difference other than pure, abstract fluff between ignoring him and "dodging and evading and whatever" - which doesn't appear to be what Legolas feels like. Despite the fact we know he can dispatch the orc ridiculously easily, and he knows that.