I would just use a HOB
filter and have a reasonable amount of live rock in the tank. Canister filters need cleaning weekly or you'll see rising nitrates. HOB
filters just need to pull out the filter pad and rinse and replace. Much easier.
A sump will increase your water volume as well as allowing you to hide many of your components like heaters, protein skimmer, refugium...but honestly, I'd skip it on a 30 gallon.
No, a controller isn't necessary on any tank. It may just make things easier.