That's another aspect I'm trying to tackle right now, transferring over the status of the old forum to the new one. There obviously needs to be some kind of a reputation translation.
Let's start by listing what parameters we have on a member. We have posts, registered days, logged in time, but have nothing on quality. We also have the reported accuracy and trust, but they don't quite work. The proposed "like" system will give us a "popularity" rating but may not be a "quality" rating.
We do have to start from scratch
Rating quality cannot be performed by every registered member, because it will be exploited. How about current senior member or hero members? The current member system is based on activity which is simply built upon days and posts, not reliable. So, giving a "quality" tag to a post should be done by qualified members in a controlled manner, otherwise rating will have no meaning or value.
Qualified Members (QM) can be nominated, elected, or auto-qualify by fulfilling a set of conditions. I am in favour of mods nominating seed QMs, about 20 in beginning and slowly working up to 50 or 100 later. These QMs will have a replenishable fixed number of Quality Points (QP) within a period to tag quality posts. When normal members have enough QPs and satisfies other conditions like post count or days registered, they can be QMs themselves and start to give QPs. You can have this system in reverse with Spam Points if you like.