what new features would you like in lf2?

[A-Man]

Lol, I am working on something similar as well (check the link in my signature). It's pretty interesting to see what you're up to though XD.
Here are some cool stuff you should have:
1-Platforming.

2-A more advanced input system which allows combining different buttons for a move.

3-Real time transformations (stretching, scaling, rotating, shearing..etc) and effects (alpha, blur, distorting..etc) which can be done through tags.

4-A variable/register system where you can actually set and play with registers in your .dat files. Maybe some already-set variables which holds the x/y/z positions, velocity, facing..etc of the character. A conditional operator would be an awesome thing to add. Perhaps some other functions which can generate you random numbers, or find resultants..etc. All that would allow some awesome real-physics simulations for moves. You should consider this early though as you might need to set the types of all the tags data as strings (so you can then Evaluate during real time); it depends on the language you're using.

5-One should be able to have more than 1 opoint in a frame IMO; Image and frame limit should be manually allocated with tags at the beginning of the .dat file.

6-One should be able to set a color key for his image in the line where you load it.

Also, you shouldn't focus on copying LF2 IMO. Focus on how you can make your engine stronger; in a way that you can mimic LF2 or any other beat em up out there, or even allow one to come up with some brand new style.
Oops. Misread your sentence.

Good luck!!!