Seems a good idea but would remain always the problem of what version to play at the tournaments.
I know that in past there were fighting game of this kind (one of them was a Street Fighter I think): do you know if the mode to use in the tournaments was just one previously accepted by all the players?
At first it was the HD Remix style. Basically, it appears that in tradition the latest version is typically the competitively played, even if the community feels that the non-latest is the better competitively.
I can't honestly answer that question because it depends on how it's remixed in balance. I would have some ideas to balance it and in my view it honestly isn't much to make it a better balanced game. You also have other things to consider, what if they put some of the doa4/doa5 characters in the engine remix mode to see how they would do in a DOA3-style system
?
Just as an example, I'd personally suggest the following changes to it:
Gen Fu's 3P+K is -7 on guard, not +2
Gen Fu's 22/88P doesn't GB and is -9
Bass' 9K, 9P9K cause juggle knockdown
Hayate's 66_P is -7 on guard
Brad Wong gets guard breaks and possibly his hand stand stance.
Jann Lee's 66K, P2PK, 6PK are -1 instead of +1. Or it remains +1 on 66K but is -1 to -3 on 6PK and P2PK.