I think you've misunderstood me or I've misunderstood you, I'm afraid. I must've not been clear enough. I meant this:
I have not read it as any person in this thread wanting open, unlimited access to any tier enhancement or PrE tier I/II/III in any PrE tree, without restrictions the same as or similar to existing prerequisites, through taking a single class level tied to those PrEs.
Because that ^ is what it seems the fears about all builds being the same seem to be founded on. To allow multiclass unfettered access to PrEs available once they reach prerequisite number of class levels is only requesting retaining the same flexibility of mixed class benefit as is possible now.