We're trying to come up with a way to allow new users just a few comments, allowing them to gain more as their comments remain on the site without being flagged and subsequently removed. You'd start at 1 or 2, then be allowed 3 or 4 per day, then 15 to 20 .. up until you unlocked the feature entirely.
It is frustrating to not be able to leave a helpful comment when what you have to share doesn't quite constitute an answer (most often, you just want to help someone improve an existing answer, or get clarification on a question).
The hurdle here: Our comment moderation tools are abysmal, and new comments don't get that many eyes on them by default. Ideally, we come up with something that doesn't require users to review comments left by users with less than 50 rep. It's an interesting problem and one I think we can solve at all scales that we deal with, but we've got to get these moderation tools sorted before we can tackle that (and other annoying new user restrictions).