Again, there ARE downsides present with liking and upvoting systems, and they offer no value in terms of improving discussions or continuing a conversation. Even if it doesn't bump up posts, Facebook posts and comments are frequently generated solely for the sake of generating likes, and reddit has similar problems (although it functions as an aggregation site, so that's kinda just how it has to work, but reposting and other things aren't done to flood the site more than it is just to generate karma). If you see that a poster is frequently making points, then share it on their user page and/or friend them, but there's no real reason to implement a thumbs up system.
That said, I'm only a section mod here, so I'm only making the case from the way I see things. I'm not an admin, so your suggestions may be considered. Whether they will be implemented is up to the discretion of the high priests.
–- Update From New Post Merge ---
'Likes' are a metal reward
Surprised you're against an idea that makes the forum more metal