Depends on what is that 3%. If they asked the designers, they will probably tell they're just fixing some details, but their way of seeing what is ready and what is not is probably very different from mine.
Just to say, they've been saying more than a year ago that the core of the system was in place and it was only a matter of marginal things, but all they meant was that the combat structure (initiative, action economy), the ability check-based resolution system and (dis)advantage rules were set, all of which are very much at the heart of the game but have been designed more than 2 years ago and probably took very little time to design since they are very simple.
However some of the 'marginal' things have a huge impact on the playing experience: skills, feats, proficiencies, multiclassing, subclasses, healing... in fact to me they are very much part of the core of the system, but they changed all these in the last year (maybe only healing was frozen earlier than that).
Some of the classes might not be even finalized yet. Some ability might still be in the limbo between being a class feature or a subclass feature, and that has a significant impact on the game (if it ends a class feature, every PC of that class in your fantasy world will have it!). But if they ask the designers, they'll probably tell you it's just a detail.
I hope that the remaining 3% does not require the designers to make any design decision but it's only about fixing effects, durations and other parameters of existing spells/features/abilities/items, based on closed playtesting results. Non-quantitative design decisions such as "should this work like this or like that" have consequences on other parts of the game, meaning more work is required to check and adjust, so I really hope they're done with them.