The devil is really in the details. Personally, I need to see more info about funding mechanisms, future liabilities created by the improvements, disaster resilience, and how this project benefits citizens outside of game day before I can pass judgement. For instance, I'm much more open to adding surcharges to ticket sales that the city taking on debt to pay for its share.
I was told by a city manager once that the key to negotiating is being willing to walk away from a deal to get what you need. So I would definitely play hardball. I'd force the Jags to justify every cent of public money and I'd get independent verification of all ROI figures presented. I really don't care about the deals other cities give to their sports teams except for the evidence of ROI we could expect from our investments and ideas that could be used to improve outcomes for our citizens.