My guess is that to do it fully effectively you would need to use a tool that filters out new posts from anyone over a certain SP. I'm pretty sure that a few tools like this actually already exist. We'd just have to create groups that curate these posts to identify potentially good new users for upvotes and delegations. With a few users volunteering to identify new users, it likely wouldn't be too difficult.
I think the main issue will actually be getting enough SP to delegate out. Because to do so you need to actually have the steem powered up. It could possibly done where individuals pick the users that they want to delegate to personally.
I think the worst thing for the limitation is actually that it will take 7 days even after someone makes a few posts to get any SP, unless they pay. I think that new users will not be dissuaded by limitations. Many of them will work hard to get those limits increased. Like when you start a new game and are limited as a player. You won't just give up because you can't fight endlessly, you'll build up your character until you can succeed.
But there's an extreme problem right now. Not only are people incredibly limited with the number of comments and posts that they can do, but there's still and incredible difficulty for many accounts to get noticed and upvoted. There are literally contests giving away money every day that are having trouble getting enough people to enter them, for free money. How insane is that?
I already chat every day on steem.chat. It's a great place to make friends and connections and just have fun. I personally dislike discord...but some use certain discord servers to make connections and get upvotes. Discord servers have a major issue getting the word out there and getting new users. From the time I was new people were like "go to discord" and every time I was like "where?" There are tons of discord servers, each with their own users and rules, and each requiring invites. Personally, I like steem.chat better.
If we got more users to join steem.chat or specific discord servers, then perhaps they could make connections and friends...but I've been here a year, have quite a few friends, and still have issues getting rewards on certain posts that I've put a lot of effort into. Of course, I've also gotten a bit more than I think I deserve on a few posts over the last year. Thankfully it seems a bit better in the last few days though.