Seriously. How realistic is jumping in half life or any of the mods to date? It's not. At all. No one gets into a gunfight and jumps around like a madman in an attempt to dodge bullets. Intelligence says you'd dive for cover, but only a few mods have coded diving of any sort, and that's diving for stunt appeal, and not so much for getting out of someone's crosshairs. Fighting terrorists? Jump out from a corner and shoot them in the head in midair. Fighting aliens? If they get near you, start bouncing around, they won't bite you then, haha! Fighting monkeys? Evil rabbits? Demons? Nazis? Jump, Jump, JUMP!!! And once you allow jumping to stay in the game, you have to balance around it. I'd love to see a game without any jumping at all.
How would I get around the map? I hear you ask. Let me ask you this. For all the realism mods there are out there, compare them to the realistic 'map' (AKA the world around you) that you've been walking through all day long. How many times today, in the area that you've walked through (which is probably orders of magnitude bigger than any HL map could ever hope to be) have you ever needed to be able to jump four feet in the air and 6 feet horizontally in order to clear a gap so that you could go about your daily life? How many times have you actually JUMPED in the last week? Month? YEAR? (jumping rope for exercise doesn't count, you dolt) I'd just love to see a game that purported to be realistic and was designed around no jumping whatsoever. Or extremely realistic jumping. e.g. - that soldier with 100 pounds worth of gear, ammo, and weaponry on his back being able to jump about six inches in the air and having a good chance of spraining his ankle on the way down. Not to mention completely losing your ability to aim a weapon if you're bouncing while you do it.
I don't particularly hate jumping, mind you. I just got off on a rant and didn't know when to stop. And it's better than working.