Undoubtedly, there were some coulda-woulda-shoulda actions that might have been taken by OPD, OFD, OCSO, or other responding agencies, but I have yet to hear any serious criticism from a reliable source. I think the issue is that people want to get paid and there are attorneys willing to help them as well as fill their own pockets. I suspect the attorneys and likely most of the plaintiffs are hoping for nice settlements from various government agencies.
I hope that the City of Orlando and other defendants vigorously oppose this suit. We already devote considerable law enforcement efforts to suit-proofing our actions. If every active shooter incident is seen as a pay day, we'll become even further crippled.