You can’t test something they don’t want to put in the game.
The crossplay we think is:
“Hey I play on Classic client”
“Hey i play on Reforged client”
let’s play together
What we get:
“Hey I have reforged”
“Hey i gave reforged even if I don’t buy the HD update”
let’s play Together
They simply left only the reforged client. So we are forced to play together. The people who think they can still wait on classic client will be a lot disappointed when reforged is release and they lost the old client.