With these rules, characters will overall become slower and have significantly limited options in combat, since they're now using half their actions just to move. First and foremost, you completely eliminated the Run speed, so everyone is already moving half as far as they would be under the normal rules.
I'm sorry if I wasn't clear in my initial post, but I eliminated the Run speed as a cap on Combat Round movement. The only movement rate that I have kept is Walking and that only applies per Simple Action.
For example, a character with a Walking speed of 8m can spend 2 Simple actions to move 16m in a single initiative pass. If he has 3 initiative passes, he can move up to 48m if he spends all of his actions on moving.
So you don't find it at all unreasonable for an average agility 3 human who's high on Jazz to be able to move at 31+ miles per hour? (three initiative passes, two move actions per pass, plus a run action with at least 1 hit. He goes a lot faster with more average hits.)
Secondly, all the other actions in the book are balanced around the idea that you can move at will.
I disagree. Can you give some examples?
Imagine I'm an agility 3 average security guard. Here are a few examples of things I would be able to do in a single pass with the normal rules, but your new rules would disallow.
1: Take cover and return fire. (Move to cover, Take Cover simple action, Fire Weapon simple action.)
2: Retreat and reload. (Move away from combat, Remove Clip simple action, Reload Weapon simple action.)
3. Take cover and call for back up. (Move to cover, Take Cover simple action, Send Message simple action.)
4. Spray and pray while running away. (Run free action, moving away, Suppressive Fire complex action.)
5. Throw a grenade away before it kills me. (move to grenade, Pick Up Object simple action, Throw Weapon simple action, spend the rest of my movement getting further from the blast, Drop Prone free action.)
6. Ready a weapon a take cover. (Ready Weapon simple action, move to cover, Take Cover simple action.)
etc, etc.
You're removing a lot of the tactical positioning from the game by forcing your players to basically stand still and shoot at each other, because they'd be wasting their turns trying to get into new positions.
I disagree. Shooting is usually a Simple action. Under the original rules, a character with an Agility of 4 and 2 initiative passes can run a total of 16 meters and shoot 2 times. Under my house rules that same character can move 16 meters and shoot 2 times. If that same character has 3 initiative passes, they could move an addition 8 meters further than they could in the original rules.
The end result of these rules will do a few things.
1: Encourage players to prioritize more passes more than the base game already does. Whoever has the most passes wins, because they suddenly have half as many actions.
2: Make combat less interesting, since so much of it is now spent not actually participating. Player has Agility 4, wants to move 16 meters to get behind cover, and fire on the enemy. This is going to take him 3 passes by your rules. He moves 8 meters and readies his weapon and his turn is over. Then he moves 8 more meters and takes cover and his turn is over. He only starts shooting by his third turn. By the normal rules, He'd run over, take cover, and ready his weapon by the end of the first pass. And if he wants to quick draw, he can return fire immediately.
3: Reduce options in positioning. You may not realize it, but you are discouraging your players from ever moving less than their full movement rate, because it now makes them feel like they're wasting actions. Let's say the Agility 4 player wants to take cover behind a wall that's 12 meters away. One simple action only gets him 8 meters, and now he has to decide whether he wants to use his second simple and waste 4 meters worth of movement, and then be unable to take cover when he gets there anyway because he's out of actions, or if he's going to take a chance rolling Run and trying to get 2 hits. If he fucks up, he doesn't even get to the wall at all. You've now given your player an annoying choice that wouldn't even be an issue in the normal game, as he'd run the distance, take cover, and still have a spare action to do something else.