I see many people arguing that Iron Valiant is broken due to its speed and move pool, and while those are true, I don't believe valiant is that hard to prepare too (compared to other top mons)
Mixed sets lack power in order to keep the surprise
and even boosting sets have selected mons it cannot kill consistently, you can say "well, encore fixes this by making it too powerful" the thing with encore is that its a move slot, so depending on coverage, you will need extra turns, and if the opp guy gives you that much, the guy was not gonna win the match anyway
Just attack the valiant
and I know what you people are gonna think "wow 1LDK, such insightful advice, you truly are the greatest of all time to come up with such delightful answer, you fucking worthless nerd"
But think about it for a sec, if the valiant got safely, he has 2 options
a) set up
b) kill you beforehand and set on the next mon