[Trexmaster]

I'd go for the simplest solution to the problem: excluding Blink from the allowable spells. (option 1)

Being able to move regardless of statuses inflicted on you (bar hard CC like Stun) without any investment outside having Whispering Cant in your skill list is extremely powerful. The OP already illustrated the issues with this succinctly.

A good middle ground would be to just reduce its range under silence so soft CC isn't completely useless against someone with Whispering Cant. (option 3)