Adjusting percentages for pace wouldn't make sense, since it's already an overall efficiency stat. Volume stats, such as TOs and PPG, could however be adjusted. Either way, I suspect it will reflect the same trend Jay has noticed so far.
Also as previously stated, I think the impact is pretty big. When you combine the ~2% increase in 3pt% and ~4% decrease in 2pt%, that is a very large difference. Once teams adjust and optimize for this new GE, results will be even more devastating I think. However, one thing to keep in mind in this stat is that there may be more outside offenses being run now, which would explain the drop in 2pt%. The true way to compare the before/after is to block on offense. When you compare the stats for each offense before and after the buffs we will know for sure the true effects.
One problem with this whole thing is that opponent strength, GS, injuries, etc. are all factors that can mess with the data. So we need a fairly large sample size in order to get significant results. Unfortunately, this is extremely tedious without some kind of data scraping (which I believe is a bannable offense). So, unless someone's got a lot of time on their hands and know what they are doing, it will be hard to come up with meaningful data.