I see both sides of this debate.
On one hand, it's damn near impossible to try and nickel and dime your best/franchise player and captain after you just went out and overspent massively on Streit. If I were Giroux and Homer came to me asking for a discount because he needs to sign Schenn and Couturier too, I'd point at his luxury signings of Streit and Lecavalier and laugh. Asking G to take $$ out of his own pocket to help the team's cap situation when you had plenty of caproom both now and going forward just a week or so ago isn't fair at all. Ultimately, if there are some cap casualties, it will be Homer's fault, not Giroux's.
On the other hand... I think 8.3 is entirely too much for Giroux given the way he played last year and the fact that he's only really had one excellent year. He's a great player, but at this point we have no idea where Giroux is going to settle in points-wise per season. Is he going to be a 75-80 point guy, or a 90+ point guy? That makes a difference. Is he ever going to score 30 goals? That also makes a difference, since goals are more valuable than assists. When Malkin and Crosby got paid, they had several years to look at to justify their salaries. Ditto Getz and Perry. Even young Steven Stamkos had several years to look at to justify his contract. Claude Giroux has ONE, and it's a career year where he still didn't eclipse 30 goals. That's scary to me. We're essentially paying for potential, but there's no upside for us. If Giroux scores 90-95 pts per year, we get our money's worth, but get no excess value. If he scores anything less, we're getting less than what we paid for. That's a whole lot of downside risk for such a meager upside.