I would say SCH would be a lot better than WHM if you do decide to play a healer. It has a lot more to do compared to the relatively dumbed-down style WHM uses these days, but WHM is almost entirely reactive now whereas SCH has a lot of emergency buttons and shields it can place to preempt large incoming damage without relying on precision timing. Once you have the strategy figured out for playing SCH, you'll be able to buy yourself a lot of extra breathing space even if you're struggling to react at top speed. It's a pretty good choice for people who like having plenty to think about without having the twitch gaming skills some other jobs require (speaking from experience here).

Other than that RDM is very smooth as people say and a solid choice. BLM is a mixed bag, as the cast times really do help with reaction speed issues but in intense fights the same cast times can make the experience even worse than for jobs like BRD.