Please add the feature that you can convert a replay to a playable world!
Similar to what Johni0702 has responded with, you might as well use the WD Mod to download the terrain on the replay, since the only "playable" aspect of what is in the ReplayMod is the blocks/map/world itself.
I have both the ReplayMod and WorldDownloader Mod installed by using a combination of Forge and LiteLoader, and it is rather a simple process, so if you would like any guidance with how to set that up, be sure to reply back. I come on the website a few times a day so I should be able to reply back relatively soon.