That was never the issue with the OP. I traded for Kirk the other day, he is my #1 FA target in another league where the FA season starts tomorrow AM.
The original question appeared to be Thomas for Kirk straight up. My consistent reply was Thomas should get you Kirk plus something, like a draft pick at least based on the majority of Fantasy Rankings.. Is was an equitable Fantasy value exercise, not which player will be better in 6 years.
I like Kirk and I think now is the time to acquire him, if not already too late. But you don't/shouldn't throw away value in a trade just because you like someone or believe they have huge upside..
You then asked me which list has Kirk #120 whatever and I presented a list that just came out that same day. I then presented a wide variety of examples including Fangraphs that showed while Kirk has a lot of Helium now and upside, but he is not yet a top ranked Fantasy prospect ... Especially compared to Thomas.
They say after the first 100, the difference between 175 and 125 is negligible... However, the difference between a guy in the top 30, and 125, there is usually some industry rational.
So again ,personally in a draft, I would take Kirk over Thomas. But If I am trading Thomas, I am not just doing an industry ranked top 30 for a guy not top 100. I want something else in return also.