I put no, because all of the cleanup work or remastering should be done when the game is 100% completed.
As others have said, other games are abandoned before being completed, and it would suck moldy monkey balls if this game ended up becoming abandoned, because the dev decided to remaster it half way through, and then real life interfered with the game getting finished.
Devote the time to finishing the game first, and then worry about remastering it.
Also, keep this in mind.
I have read a lot of comments in various games, and devs who have too many unfinished games end up with really shitty reputations. No matter how good the work was, if they leave too many games unfinished, they will piss off the patrons who support them and adversely affect their future income.
No one wants to invest in devs who have gained a reputation for leaving games unfinished.
Also, there are games where the devs are doing all of the bug fixing and image updating as new releases. But they are not adding new content or they are adding very small content updates. It's pretty much the same thing as you are talking about.
The time wasted fixing the little issues leaves patrons with insanely small updates because of the time wasted on the little details being changed in previous releases.
One dev who I will not name here, has released his last 4 updates that have had no new content added, all 4 updates were nothing but fixing the little crap and updating images in earlier releases that could have been worked on after the game was finished. I was a patron of that devs game and dumped it, because I really hate paying for NOTHING...
As for merging the older with the newer versions. That depends on what the total size would be of the two merged games.
But, if it is really just a case that you are running out of ideas for this game, just ask here what direction that they would like to see the game go in. The people here would love to have that kind of input in the game, and will be sure to let you know what they would like to see.
Those suggestions might just be ones that get your mind going again on where to go with the game.