Pho, I don't think people are undervaluing IT4 (if ever, probably only slightly) and I think the differences between the 2 players stem from it being easier to stop IT and also how easy it is to build around Lillard.
Let's face it, CBS is a brilliant coach and he's put guys in positions to succeed. Evan Turner's resurgence is another great example of this. I think most (if not all) of our guys are overperforming under CBS. If you put our guys on another well-coached team (like the Spurs), they'll continue to do well. Put them in Charlotte (or Portland? or Philly?), and they will suffer.
I really think that if you switch IT4 and Lillard, I think IT4 will begin to struggle in Portland (if not his numbers, his efficiency will take a hit) and Lillard will continue to shine here in Boston, if not more so.
This isn't IT's first team, you know..he did pretty well for himself in dysfunctional Sacramento. I think you are overselling how easy it would be for other team's to stop him and giving too much credit to Stevens. IT is the one player who
finally made Stevens' job a little easier, not the other way around. Before Thomas, Stevens was..I believe..41-87? Since Thomas, the Celtics are what? 35-21?
There is literally no evidence to what you are saying and everything actually points to the opposite considering he has now played on three different teams and played at similar production rates on all three with similar efficiency. If anything he is actually playing a tad bit worse right now than he did in his final year with the Kings, and it's still on par with Lillard.
Every player's efficiency takes a hit when you play with less talent. Lillard was a 56% TS guy the last couple years with LMA. Now he is a 54-55% TS guy with more of a role. He's taken a hit. IT was a 57-58% TS guy in Sac (Cousins) and Phoenix (Bledsoe + Dragic). He was actually a 57% TS guy for us in the remaining half of last year, but now he is a 54-55% TS guy this year. Fits the idea that if you play with less talent, your efficiency will take a hit. It has happened to Lillard in Portland, and it's not related to his height.
IT has already proven for years now that height has not significantly hurt his game on multiple teams, with many different players, and different systems. This isn't really something we should be questioning anymore. He will always be a 54-57% TS kind of player. It's who he is and we have 4+ years of data now, Stevens or no Stevens.
So yeah, he was definitely significantly undervalued in free agency, and it appears to me that was more circumstantial than anything which I pointed out a bit earlier. Pre-conceived notions about a player's height, "big numbers on a bad team" with only one year of 20/6 play, and dysfunctional franchise with limited national exposure all rolled into one. IT had no leverage going his way whatsoever in negotiations, and the Celtics (well Phoenix..) ended up with an all star type player on a great, undervalued contract as a result.