I think that having new players play against 1200s and 1500s is harming the ladder population. Now I don't know exactly how the matchmaker works but the result is a lot of downsides and no real benefit that I can see.
New players can easily get discouraged playing against people way above their skill level. They don't learn anything from getting crushed in 6 minutes, or by being overwhelmed with random advice from some well meaning opponent. It's true that you need a bit of a thick skin and patience to improve in supcom but newbs should be able to learn at their own pace, against players of their own skill level. A new player that I befriended told me he was still playing against 1k rated even after his 10th ladder game, and after stabilizing at 300 points. Granted this may be because there were no other newbs searching, but the point is he was made to think that playing against people 700 points over you is normal. That's understandably a tough idea to face and made him quit ladder entirely. If he had started against new players and had time to build up confidence, I think he would still be searching today.
It's not exactly fun for the more experienced player either. It feels bad knowing that you might be the reason someone quits, or spending 20 minutes giving advice and explaining stuff when they might not even come back (and with good reason if they think playing against someone with 200+ games is normal for newbs). Other players I've listened to seem frustrated by this; it certainly puts me off searching ladder when I know that most of the time it won't be an actual game but 20 minutes of talking and then steamrolling with 40 blaze tanks because I get bored.
And don't get me started on the new players who search when no-one's high enough to play against them. If you ever visit FAF during dead times you'll see why many new players think the ladder system is broken. There are many timezones that simply don't have any regular ladder players in the 1-1.5k range, so no first timers can find a game to get them started. I'm not saying that reducing the starting rating will turn Australian FAF into ladder heaven, but I think it would help a little. At the very least if a newb complains about getting no 1v1 action you can simply state that noone his level is searching, instead of explaining how he has to return 7 hours later whereupon he will get crushed several times in a row.
high starting deviation and playing your first game against mediumish ladder players doesn't deter smurfing either. In fact, I'd say it actually encourages smurfing as ~1k ladder is still pretty relaxed (and we rage and call everyone a smurf which gets them laughs). If they feel like playing against newbs anyway they can simply lose the first few games on purpose. And at the same time, because the system treats new accounts like an average player they give the same rating when defeated. I've probably grabbed about a hundred points from games where I shouldn't earn any, I'm sure others have gained more.
It's pretty clear to me that most 0 rated accounts actually are new, and not returning 2013 pros, GPG vets, or old players on a fresh account. Of my last 5 ladder games, 4 have been against people who were completely new to ladder, only one of which had played a couple teamgames before and gotten a bit of global rating. Why can't they play against each other?
I'm not saying we should have them fight only against other 0's. Perhaps shift it back so they look for someone in the 0-500 range and slowly widen the search if noone's within that rating. But please do something, this is making new and old players alike stop playing.