Well, option Nr.1 is too complicated and can lead to lots of new issues. You can not always join arbitrary tables, not when it comes to DQL where it alters the overall result. The situation is much more complex than it might look to you right now.
Nr.2 is no option at all because such a proxy approach does not even hold for instanceof checks. An absolute no-go.
What it does now is the best thing from my point of view. If performance becomes an issue you can always improve upon that by eager fetching with DQL. Also, you did not yet understand how it works. The eager load does not happen always with class table inheritance, only when the target entity is a base type. If it is a subtype that does not have any further subtypes, then a proxy can be used without fear. Same goes for single table inheritance.