I tried out the Monogame Framework (based on XNA) to get a grasp of how it is like writing a game without an engine. You have to think about how to organize your objects a lot more this way and you have to write your own utilities. Conclusion: This will take forever, but it's quite cool.
Writing a custom editor for placing tiles.
Batching does not look good.
Concept of the game architecture - not comprehensive.