I don't know all the details of you previous tank, but I'd venture to say that you had problems with your plants due to inadequate lighting. Some of the plants you mentioned require medium to high light, and the stock LED lights on all the Fluval tanks are basically only good for low light plants. You didn't mention anything about fertilization (substrate or water column), and that probably led to some of your difficulty in being able to keep your plants alive.
I recently rescaped my Fluval Spec 2. It looked like crap before with jungle val being the only plant that was doing well. I had flame moss and another type of moss that wasn't doing well. However, I'm now adding Excel and liquid ferts, and all the plants including the the moss are doing much better. I'm even seeing growth in the rotala that I have planted, which didn't exist prior to the rescape.