Would a hot tub be easier to maintain / more desirable?

Of course, not as directly labor intensive as what you are embarking upon, good luck in your endeavor.Amazon.com: The Hands-Off Investor: An Insider’s Guide to Investing in Passive Real Estate Syndications: 9781947200272: Burke, Brian: Books

Maybe a super hot unit on South Beach or something in DC i'm emphatically confident will turn substantial appreciation in the very near further.

It's just very capital intensive to go forward with this strategy.

Your goal with a property shouldn't be to hold it forever, it should be to build enough equity to use that to buy another or to sell when hot and turn it into two assets.

INvestors would drop him like a hot potatoes.. so far that hasn't happened. 

Many of the older homes that haven't been renovated will not have insulation or HVAC, and will certainly be needed to be comfortable during our really hot summers.We ended up doing a BRRRR (Which we ended up selling due to the hot market a few years ago), and it was almost a complete gut, so I'd be happy to discuss numbers with you.

Clearwater and Tampa are hot STR markets for sure  

Current hot water heater is 21 years old in a 2 bed/1bath SFH that is being flipped into a Mid-term rental unit.

It would be interest to look at prices in many of the hot secondary and tertiary markets, where I think you can often get more bang for your buck.