However, wouldn’t you expect that the game designers did quite a bit of controlled testing before changing the first turn rule a while back?
Sometimes PCL* doesn't do what we expect them to have done.
Sometimes PCL makes mistakes.
Sometimes PCL may not have had the time or enough testers to find a satisfactory answer.
Sometimes PCL doesn't catch on how future changes will affect the game until it is too late.
It helps to know the history of the first turn rules. I do not believe the first turn Evolution rules have changed over the years, but remember they apply. Oh, and specific
rulings related to those first turn rules
have changed (I think Rare Candy had some examples of this), but the core rules for Evolving remained the same.
1999 to 2004(?): No first turn rules.
2004 to 2007: T1, the player does not draw for the turn and cannot play a Supporter.
2007 to 2011: T1, the player cannot play Trainer cards (modern definition) from hand.
2011 to 2013: No first turn rules.
2013 to present: No T1 attacks.
Given this history, including the return to "No first turn rules" requiring an
early, emergency set rotation that year, happening a couple months ahead of the usual schedule, I'm pretty sure all of those "sometimes" exceptions I gave apply.
I believe there are two things they strive for with the T1 rules:
Keep it super simple.
Make it balanced.
I'm not one of their testers, so maybe they have considered my ideas - or anything else mentioned in this thread - and it didn't test well. Then again, they somehow missed how broken so many cards were in Base Set. Simply put, sometimes players approach the game with an unanticipated mindset. I mean, there are multiple cards in the Base Set that weren't just broken then, but would still be broken
now! XD
*Pokémon Card Laboratories - Also called Pokémon Card Game Laboratory. The division that designs the cards and does the R&D for the Pokémon TCG.