I made a game mode that is more friendly for new players. It is the mod (in the mod vault) called "Stone Age." It takes away everything above t1. This takes away a lot of complexity. You don't have worry about TMLs or making SMD or building flak to counter gunships. It also strips away your ability to eco in place by upgrading mexes, which means you don't have to worry about balancing between unit production and growing your economy. Pretty much all you can do is spam land (or air) and expand, take reclaim, raid your opponent, pick fights where you can win (to get unit advantage or to take reclaim) and eventually try to kill the enemy ACU or destroy their base.
The idea is that new players can practice the fundamentals (balancing power with mass income, spending mass, scouting, raiding, fighting, reclaiming) without being led astray by temptation: the temptation to make t2 mexes, the temptation to get high-tech "toys" to play with. Learning how to spend all of your mass on t1 production is a skill that players need to learn if they want to get good at ladder.
A lot of low-rated people make too many t2 mexes. It's a crutch. "Oh, I have too much mass, I guess I'll make a mex." Take that away and they're forced to learn how to spend their mass. A lot of low-rated players can barely even IMAGINE making 10 t1 factories in a game. It's like their brain doesn't even think it's possible. Give them no other option, and they'll learn to do it. So it's both a teaching tool as well as a more comfy environment.
I suggested making a matchmaking queue where every map is a 5x5 or small 10x10 with not much water, with the stone age mod, and people don't get to pick their factions. Red will be Cybran, blue will be UEF. That's my idea of a simple noob-friendly matchmaking queue.
I wouldn't say this makes the game "dumbed down," you can have some pretty intense competition with T1 only. I have to agree with @Askaholic that making a "dumbed down" version of the game would be a bad thing.
The problem with trying to learn the game when everything is on the table is that too much is going on for people to learn anything. I think a lot of noobs try the ladder, lose horribly, and even if they keep going back, they draw the wrong conclusions about what they need to do better. E.g. they worry about whether they went t2 too soon when their problem is they didn't expand and raid enough. They want to be the "Supreme Commander" "Master General" "Brilliant Tactician" so they're more focused on strategic-level decisions (do I get t2 air or should I get t2 land) instead of mastering the logistical side of things (just making sure you're spending your mass, have the right amount of pgens, your units aren't idle, you expand where you can, you scout, you raid, you use what you got in an effective way). That's why they would benefit from taking away everything above T1 and just drilling the fundamentals first.