Your whole argument is why Winnipeg needs Trouba, and then you end it with an unrelated conclusion.
Why should Trouba stay in Winnipeg?
Seriously IDK what I was thinking. Fixed it now. And to answer your question, what other options does Trouba have? Play there or not play at all. My earlier post explained why holding out and hoping for a trade wouldn't work, so it would be stupid to try to force a trade that way.
If he wants to maximise his earnings, the absolute best option is to sign long term (6x5,25). After the six years have gone, I'd assume that Winnipeg will be a playoff team or even a contender by that point. At the end of year five, Buff's contract runs out, and Trouba has one year left as the leader of the defense, setting himself up with another big contract from a playoff team. As a 28 year old defenseman, he can easily get a big, 7-8 year contract then.
If he goes for a bridge deal now (2x2,8, Ryan Murray's bridge as a comparable), he'll be two years away from UFA after that, but there's a big problem for Trouba. Stuart will still be in Winnipeg during those years, and Buff will be the #1. There's a decent chance that Trouba would play with Buff, but if Stuart is still causing problems, Maurice knows who can carry Stuart.
That will damage his numbers more, which will affect his paycheck, and above all, offset the benefit of signing a bridge deal in the first place. The other downside to a bridge deal is that Winnipeg has a lot of expiring, big contracts that year - Ehlers, Little, Enstrom to name a few, and if he has to go through the arbitration, there goes even more money. In his situation, a bridge deal will cost him a lot more than you'd think.
Long story short, Winnipeg can offer him the security of a long term deal now, but being problematic does not help his case at all.