I am not calling TJ a "pussy." If I did, I was wrong, and retract that statement.
I am saying, for me personally, I am not going to think TJ is an extra special fighter, because he went down a weight class to beat a smaller man. The guy is an already great fighter. If he wants that "great fighter with an extra layer of special sauce" label like guys like GSP, Anderson Silva, Jon Jones, Demetrious Johnson, in my opinion, he would have to step up and fight Max Holloway/Frankie Edgar.
Beating DJ will carry that "but you beat on a smaller guy" asterisks. Yes, DJ hater will celebrate. However, the rest of reasonable fans who understand what p4p actually means, will always say "yeah, you beat a smaller guy."
The glory of TJ vs DJ is more on DJ's side. DJ is the one who will be facing a bigger critically acclaimed fighter.
In terms of legacy, TJ is "Floyd Mayweather" in this situation. Like Floyd Mayweather vs Conor McGregor, TJ is the one stepping down a notch. A DJ win will have bigger shockwaves across the MMA community, than a TJ win.
If TJ wins, the best we will say is "yeah, he is a good fighter. We already knew this. How does beating a smaller guy make him any better?" This will even be more pronounced if TJ loses the BW belt. If TJ beats DJ, and fails to dominate the BW division (guys his own size), how does that help his legacy? LOL