That's bending over backwards to explain why he doesn't run, in my opinion. Making up a nearly impossible standard to explain past behavior and justify that suddenly things are going to change THIS time.
Nothing is bending over backwards if I tell you that I expect the situation to get better but the team still will not be a fast pace team.
There are two elements needs for efficient fast-pace teams - good execution on offense from the PG position and good defense.
The Seattle Supersonics under Nate were horrible defensively - not a big surprise when the best big-man he had was probably Danny Forston (or was it Reggie Evans? Does it matter?). Add the fact that he had pretty crappy point-guards for most of time - and it is clear that his record in Seattle (over .500) was actually fantastic. He tailored a good system to a team with good shooters but crappy defense and sub-par creation from the PG position.
The Blazers, under Nate have gone from a weak rebounding team with sub-par defense to a very good defensive team with fantastic rebounding - the next step will clearly be something that is willing and capable of pushing the ball in transition. Blake, valuable as he was - is not that player - as shown during his Denver tenure. Brandon is well known for imposing his own pace on the game than the other way around and Sergio was a running disaster.
Miller, has historically been a much better PG in fast pace than anyone we have seen in the red and black for quite some time. Adding the fact that this team has good rebounding, is not bad defensively anymore and now has a willing and capable point to push the ball - yes, I expect them to get better.
If you choose to look at history but ignore the picture as a whole and point only to the facts that support your pre-determined theory - sure, why expect change. I think that when one realizes that the combination of defense, rebounding and good ball handler that can push the ball and make good decisions in transition is a unique combination in Nate's history as a head coach - so yes, I do expect things to change.
I do not think this will be a fast pace team - but I think it will be faster. My expectation is a San Antonio like pace when they were winning all the time, 20-25th (they were 27th in pace last time they won but 23rd and 20th the times before) - Good defense, Great half-court execution and when the opportunity is there to push - they will. The now have the athletes and the basketball IQ to do it. It is not Nate that will determine it - it is the players. Good coaches tailor the system to maximize the talent of their roster. Nate finally has the roster that will be good pushing the ball - and I expect him to allow them to do that.