Trygon is not immune to 5 out of 9 spheres. You assume thorn is played over sphere of resistance. There are 13 spheres, and trygon predator is 'immune to 5'.
Sure, if you want to include Golems, there are technically 13 sphere effects. You are correct, Trygon is only immune to 4 of the 13 Sphere effects, while Mana Drain is immune to 0 of 13.
But trygon costs more, so if you would Use that line of thought to compare the 2, the trygon player always starts play with a sphere effect to which it is not immune. 100% of the time (drain is uu predator is 1ug).
That's correct. I will add that 100% of the time, Drain costs UU and sits in your hand until your opponent casts a spell, while every single sphere effect that the opponent plays, in addition to other disruption, further sets back the possibility of casting Drain. Also, 100% of the time, if I have mana at my disposition (for example, when I am on the play), I can cast my Trygon Predator and force my opponent to deal with it immediately or run a high likelihood of losing the game. 100% of the time, I cannot use Mana Drain to play this role.
This means that 4-9 out of 60 depending on shop build, you will have 2 spheres against you when it comes to resolving predator.
I am not sure what you are implying here, or why it is assumed that every time a Predator is drawn, casting it would always be in the face of multiple sphere effects. Perhaps I am misunderstanding.
Winning 90% with predator on the table is nonsense. People play with duplicant and trikes . If you would play energy flux, I would be more inclined to agree with you since shop has 0 answers to enchantments and has trouble paying the mana cost and even then 90% is a lot.
Indeed, I can't actually defend that number, so you can feel free to disregard it. The intention of the statement is not to provide a statistical absolute, but rather is meant to indicate that when Predator resolves, it is a huge problem for a shop player and it is very difficult to remove. Yes, shops do play with Triskelion and Duplicant, but they have no way of searching for answers and very few ways of protecting them, so the window of opportunity to remove the Predator shortens as the game goes on.
I do not favor drain over trygon particularly, but your reasoning is flawed and your arguments incomplete.
Interesting. Since my reasoning is flawed to you, perhaps you can explain why you prefer Trygon to Drain. I am curious as to what those reasons are.