I also think that Posts and especially Likes are far more important than "10 Years" .. I see some people with the 10 stars badge but only have a few dozen posts and a handful of likes, yet they have a badge while someone who has made 5000 posts in 3 years doesn't have the equivalent.
If you find having one badge for each is a little much .. Maybe have the "star badge" be more of a combined thing. Like for 1 star you need to be a member for 6 months AND have 500 posts AND have 500 likes. Double that for 2 stars etc .. That way those showing 10 stars really have been the most solid contributors to the community being members for at least 5 years with 5k posts and 5k likes. Ensuring you won't have someone return after 12 years of being inactive making their 3rd post ever showing with 10 starts .. which if you ask me .. makes the current 10 star badge not just meaningless .. but also misleading.