Count me as someone who is not a big fan of Lawson's. Check out:
http://www.basketball-reference.com/players/l/lawsoty01.html
While his assists are up, his FG% and 3Pt% has gone down almost each year since his rookie year in 2009-2010. And his per 36 hasn't improved in most categories, but gotten worse. To me this is not a good trend, but an example of "buying high". Count me out.
I think you're overanalyzing a bit. His shooting is down just slightly and has barely changed since becoming a full-time starter (54% TS this year, 55% each of the last two). He's pretty much a lock to give you 45/35/75 shooting, 8-10 assists, and gets to the free throw line. His defense is at least above average despite his height. And for this, he's getting about 80% of the current max salary for 2 more years. Current ranks amongst PGs:
Points: #13
Assists: #2
Assists/TO: #2
FTA/FTM: #3/#4
In short, he's a top-10 PG in his prime, with a reasonable contract, who for some reason is available.
I certainly value defense, which is why I'm so optimistic about Smart. But what is special about 45/35/75? In today's game those numbers, especially the 35% from 3-pt, are not all that good.
Whether his shooting has gone down "just slightly" or not, they've still gone down. He became a starter in 2011-2012 when he averaged 34.8 minutes/game. During that season he averaged 16.4ppg on 48.8 fg% and 36.5 3pt%. Now in 2014-2015 he is averaging 16.9ppg on 44.7 fg% and 36.0 3pt%. That's a 4.1 fg% drop, which is more than just slightly in my opinion. But most of all, his scoring has been trending downward. I still stand by my opinion that I don't want to trade valuable assets for a player who is at best not improving.
If you look at his fg percentage it also coincides with the nuggets record. Maybe he shoots better with better players around him.
2011-2012 he shot .488 and they won 38 games and lost 28.
2012-2013 the won 57 games and he shot his best percentage.
The last two years the nuggets have been terrible and his fg has dropped. Maybe the nuggets want to rebuild. It's similar to rondo in theory although Lawson is a better scorer, shooter and free throw shooter.
I am a huge fan of Marcus Smart and would like to build that way and through the draft but I think if we can still put together a sure thing we have to look at that. It was no different than when we had Rondo. We had to look at those scenarios. I don't think that changes.