As with most maps, it will come down to execution. i think the concept of having a TD where the towers spawn defenders is good, as it is something not to commonly seen. The most difficult thing about tower defenses is balancing and giving people a reason to play it again (i.e. different races, setups, etc.). Not getting feedback is something you will have to live with. I have the same problem with some maps. Best way to just host them online from time to time and collect direct feedback from the people there. - in short, if you enjoy making the map and you yourself like to play it from time to time, then do it.