Would the 3 races still be balanced if walling was impossible? Just imagine a map with no choke points close to the bases... What do you think?
No. Terran would have a major disadvantage. Zerg would have a major advantage. Protoss would be in the middle.
On the other hand, the need for terran to wall in (presuming the terran does no marine rush), makes him rather easy to contain, I usually win when carrying the game to late game, even though terran always has a stronger army, I have a stronger economy, and if he doesn't super micro his units or harass me, I win. Not glorious, but still. That said, I still struggle against mass thors. They are just soo strong. I gotta try massing ultras next time.
Yo! I haven't got round to playing the other two factions yet, only Terran so far. Can the other guys not wall then? Or do they lack the ability to lower/lift off/sell their structures to let their units out?
Protoss usually don't want to wall completely, since they don't have anything that can lower like the Supply Depot. They just leave a gap big enough for units to get through, and when an enemy comes knocking they plug the hole with their own units. Zerg don't wall at all/rarely. Just when they're expecting a rush I've seen people put up Evolution Chambers infront of Spine Crawlers.
No chokes = zergling rushes would be the only legitimate strategy. If you got zerglings in your base as protoss, and mostly as terran, you are screwed.
Although some top terran players do not always wall off (usually do vs zerg), getting rid of the possibility to do so is just not a very good idea for balance. It would make ZvT pointless since each game would go something like this :Zerg 6 pools, gg. On the bright side, no more Zerg QQ so I suppose in terms of peace on forums your idea has some merit... ^_^
I agree, zergling rush would be the only viable strategy at this point. Without walling in your base early, you get rushed quickly. It would just be too obvious, especially in twos, to rush zerglings and make your opponent feel the pain quickly. I don't think blizzard will do it, but if they did, zerg would be on top in my opinion.