Cyclo I don't think it's inconsistency. He's just been on a downward trend.
I don't think it's any coincidence that Douglas weak form has coincided with playing against the AB's and Boks. The fact his despite all the praise for him last year, he was never on the field against either of our most regular opponents for more than 10 minutes.
He had an excellent work rate in the first Bledisloe even if his impact wasn't as good as expected. The fact is that no players' really was. But in that game he had something like 33 ruck involvements, 10 tackles and 6 runs in his 80 minutes. But it should be noted that in 49 minutes Simmons made 1 less run, 1 more tackle and still hit 10 rucks.
That's great involvement from Douglas. Over the next 2 games he made 11 total tackles and 3 total runs in 160 minutes. He still hit over 25 rucks both games, but despite less carrying and tackling his ruck involvement declined. So he went from 49 involvements to 35 for both of the next 2 games.
Then on the weekend in his 35 minutes, knowing that he was on for less than a half and therefore not needing to pace himself, he 14 total involvements for that 35. Pro Rata'd that is then 32 involvements. So from the bench with a short sport he's doing less per minute essentially.
Interestingly him and Simmons have the exact same involvements when you base it on per 80 minutes.
But I think Simmons are dragged down because he went off injured in 2 games, and the only game he played 80 was the Argentina game where Australia only secured 36 rucks (the next lowest in any game we played was 66) meaning his 9 rucks in 80 minutes meant he was still involved in 25% of the rucks we secured (that said, it's not high - around 30-50% of total rucks won seems to be the high end for players), but drag his total down significantly as it accounts for close to half the minutes we played.
For Douglas to partner Coleman surely he needs to be a better LO option, but he needs to maintain his work rate from Bledisloe 1. Coleman offers the impact to justify floating in and out at times, plus he is great in the line out. Douglas offers the occasional big tackle, or big clean out, but still plenty of ineffective rucks and runs, and in his career has played 80 minutes of testing rugby whilst barely even touching the ball.
Anything less than that work rate goes back to exactly what Forcefan identified during the RWC where compared to the All Blacks, or Tight 5 just doesn't offer enough of a work rate.