Would be nice there's an option to show name above nameplate, like default WOW, instead of below.

I think this might be something specific to a certain theme, however I don't recall any theme having the name below the nameplate of the top of my head.
Which theme are you using?

Generally, I won't spend time on adding features that only affect a single theme. So your best bet for this would be to edit the NeatPlates_Slim_Horizontal.lua file yourself and re-position the name and whatever else that would have to be moved as a result of this change.