For what it is worth - my close friends were split on whether or not I should do the trade. In retrospect, I am glad I did the trade (at least thus far). I have completely replenished my bench with more real high assets (McKinnon, Fuller, Kamara, Thompson) - so I still have a nice mix of guys for RB2 and Flex. Marshall going down is annoying, but I wasn't expecting much more than WR4 out of him anyway.
I do think the trade was close though. I value Landry, Hill and Thielen VERY highly. All great in PPR. I drafted Thielen and Landry in my other league (where I am also 4-1 and in first place).
I also think Ty and Hill are a wash. I think Ty has good chemistry developing with Jacoby, and should be good with Luck too. I think they are both boom-or-bust guys. Hill was just about to have a so-so week before his punt return. They are both very similar to me.
Walker/Gronk is an obvious and clear upgrade.
Thielen and Landry are both very desirable PPR guys and Marshall didn't come close/won't going forward.
Johnson was really the wildcard to me. IF the Cards have a reason to play those last few weeks - he should play fine. He hurt his wrist, and not something like his back. He SHOULD be able to play at his normal level. At that point - having Ty with Luck, DJ back and a healthy Gronk would make my squad a tough matchup in the playoffs - which is what we are playing for.
I think I leveraged my (at the time) 3-0 record to invest for the future by taking a temporary hit (no DJ, Ty w/o Luck, etc.). I do think the trade made sense both ways though.