The feature has already been implemented and tested, and we'd like to move on immediately to the reward curve in 18. If it's abused, we will see such soon, and address it quickly in 18 or 19 (or via other means).
Fear of minor abuses of rewards allocation isn't something to worry about; we're doing regular hardforks and if there is a serious problem with any change, it will be reverted or improved quickly. The point of the comment rewards pool is to directly address one of our community's biggest existential threats: our retention rate for new users. It's a lot easier to comment than to write a new post, and by ensuring that users who only comment can also earn meaningful rewards should improve that a lot.