I put my vote on more event sheet features. Just seems like basic functionality and should be prioritized imho.
Secondary picks would be Online Multiplayer and Better Tilemap Support.
When it comes to tilemap suppport I'm a bit curious about what you have in mind for it.
Something I think would be awesome is if tilemap support would include something like an alternate editor where you can make a map which you could load at runtime. Hopefully this could possibly allow for seamless transitions between maps/layouts (that'd be a kickass feature, seriously).
Another benefit I think could come from this would be to allow the placement of game logic dependent objects (spawners, detectors etc), not only environment/obstacles, as well as using layers within those maps.
When it comes to multiplayer. While I did have multiplayer as a secondary pick, I went with event sheet functions instead because multiplayer is a BIG thing to tackle (I mean, just look at Capcom... ). Maybe you could do it incrementally. It being a choice on the poll suggests that you have a plan for it though. But even so, I'll bet it's going to require a lot of time put into it to make sure it works. I'm all for multiplayer, but functionality has the priority atm.