Yes, a core that averages just over 29 is ancient... The trade does very little to help the team, as JBB isn't entering a rebuild. Neither Krebs nor Jokiharju are anything special, and a couple of picks that again, may help the team 3+ years away given Tampa's glacial development speed, aren't worth losing Cirelli and Cernak.
By all means though, continue with your doom and gloom narrative because Tampa won't trade valuable young pieces for lottery tickets.
Tampa will have the cap space, provided JBB moves out Sheary, Jeannot, and probably Perbix, to keep the players they need to keep(Stamkos and Duclair or another similarly priced F), and still be able to add one depth dman.
I'm not in favor of losing 40 goal, ppg scorers(Stamkos), or trading important younger core pieces(Cirelli, Cernak, Serg) for underwhelming returns. I would consider trading Cirelli as part of a deal for an actual top 4 dman, and if Stamkos wants more than.what Tampa can offer and still improve the team, he can walk.
Tampa is still a strong organization, and while no longer at the very top as they were a few years ago, with some better depth adds and a rising cap, there is still time for this group to contend for another title. The defense needs some help and a new system, plus hopefully not having Vasy and Serg miss a considerable amount of time next year, will also improve. It's not time for a rebuild, despite the hot take, knee-jerk reactions from some Tampa fans on here.