LOL! You'll be fine. If you are connecting in DEN and have a 30 minute layover, I bet you're flying United (UA) versus Frontier or Southwest. If so, good luck for just flying UA
While UA has cleaned up their act quite a bit over the past few months, you may still have departure issues in DEN simply due to the airline integration problems. Also if your flight from SLC is delayed, it is likely the plane you're taking from DEN to MCO may also be delayed in arriving.
Delta is notorious for changing aircraft more than once as the schedules are amended as the departure date gets closer. With DL, I generally keep an eye on the reservation either through DL.com or better yet via a tracking site like TripIt. Award Wallet was the BEST, but DL killed their interaction via the website.
Bottom line, you want to know about the change before an email is sent, since these are slow to be delivered. If you watch it yourself, then you'll be positioned to grab the seats yourself once the system rearranges everyone.
The good news is that DL has the best in-flight customer service out of all the legacy airlines, IMO.

Also if you have a problem, the @deltaassist twitter is the fastest and most responsive way to communicate with the airline.
https://twitter.com/DeltaAssist Frequent Fliers like this option over their elite call reps many times.
In addition, if your schedule changes by an hour of more, DL is excellent at allowing you to change your flights to whatever flight you want as long as the origination and departure cities are the same. Thus if the flight you really wanted was too expensive, they will allow you to get on this one for free (pending availability).