^Nobody, expect a visit from the folks at Temporal Investigations.
Ice Queen, I think Ezri proved, more than any other Trill, that the host remains in complete (and in her case, somewhat inept) control. There is certainly an adjustment, but that's to be expected when you haven't had years and years of preparation, examination and testing.
Remember, the Trill are symbiotic, not parasitic. Basically, if the symbiote just takes over the host completely, with no regard to his/her own personality, then it has gained exactly nothing. It should also be noted that the symbiotes can live perfectly natural lives apart from humanoid hosts, thus they have no inclination to become parasitic.
But all that is just the Trekkish stuff. It's important to understand that one does not have mutual congress of a single mind. Rather, you become a kind of "new person" with every joining. The individual lives lead by the hosts prior to joining is the only memory any joined person would have of "a separate life".
The equation works kinda like this:
Dax + Joe = Joe Dax
Dax + Ice Queen = Ice Queen Joe Dax
Dax + QCzar = Qczar Ice Queen Joe Dax
Odan + Joe (-Dax) = Joe Odan
In other words, whoever is Dax is one person, not three or twelve or twenty. That one person is composed of multiple personalities and life experiences (prior to joining). All of the experiences of 'Dax' while joined are of the one person. Ezri's memories of being married to Worf are Jadzia Dax's memories. Her memories of being accepted as a host are Jadzia's alone.
So I guess the answer to your question (Ice Queen) is yes, you would remain an individual in control of your own actions. But you wouldn't remain Ice Queen. You'd be subsumed into Ice Queen Dax.