The mixed feelings usually stem from all these new luxury condo buildings coming up (e.g. $1M+ studios plus large HOA fees) while we have lack of affordable housing. To be fair, there are a few workforce housing projects ongoing as well.
That's a good question, and what's interesting in no press releases or other marketing materials about these new skyscrapers did I see any mention of sea level rise mitigation strategies.
I'm pretty certain it's not king tides that generate those pictures of flooded Brickell/Downtown you're probably referring to - it happens during torrential rains. King tides alone don't do anything like that, but they obviously add insult to injury if combined with heavy rains.
On the county level, there was a proposal to build a sea wall, which met unanimous opposition, basically people felt it's gonna be like this and ruin Miami's visual allure (same central Brickell area behind Santander):
There was a more aesthetic plan with new islands and reefs but I cannot find it right now.
Ultimately they might also try and raise some parts of the city as was done in Seattle and Chicago.