With 10/10 would be castaway in the current format.
Bill get an 8/10
Very underrated card in the "current" format.
Certain decks Bill's works better. I can easily accept understand the thought that TVR's are better, but Steven's are dogs. Cosmos aren't bad, but they all fall in the class of sequencial draws. (Thus you don't give up your hands like copy cat, oak, or wager.)
+Steven was great when SS Dunsparse was ran in every deck that filled most bench's at least 4 pokemon by turn 2. In the current format, Steven's for 1 or 2 doesn't work.
+TVR's work well when there are match ups were you don't need large amount of cards in your deck for certain match ups. Thus if you run 4 cess crystals, and 4 Crystal Beach in a certain deck, then TVR will help you get rid of the cards if you mirror match. And obviously it works well in decks that need to discard nrg and stuff. (Blissey)
+ But if you run buffer pieces and plus powers, that very few cards you would want to jetison, then you run Bills.
At the very least, I would argue for versatility in the trainer lines. If you want to play straight sequencial draw, play 3 Bill, 3 TVR, and 3 Steven's. You will often find your self with 2 of the same draw card in hand and see which one you decide to play. (if you can think.)
We have several decks built, many use Bill's over TVR. I have many 4 castaway 4 Bill's and then 4 Wagers/copy cats in my deck bags. Many might disagree, but that is my 2cents.