I said at the time when Waller signed his extension it too early and he was accepting a lower value. I get why he did, but his trajectory was on the way up...he would command MONSTER contract numbers right now.
He's still learning to play TE that's the scary thing. Right now, he's probably faster and more explosive than Kelce and Kittle, and he's got a higher ceiling given he's still got room to grow physically. Raiders still don't throw his way as much as they should. Waller is literally learning to play the TE position at the highest level...that tells you how much of a freak athlete he is playing a position he didn't play until about 5 years ago. His numbers are only going to get more ridiculous as the years go buy and he learns the nuances to the TE position and his body develops.