Hey, don't take out the tree! I got a tree growing in mine too, not sure if you seen this pic but you can do great stuff with taiwan moss - OLDER PIC
I'm trying to recreate that but with .... a bigger tree. Anyways, if you dose dry fertilizers then you won't really need those substrate. They come load with the stuff, you still will need to dose trace.
I say, pick the substrate that looks best in your opinion. To hell to the nay sayer (except for me) as they will not be the one looking at your tank. It's you who would be looking at your tank the most.
I had blue and green gravel and fake plants once... it was horrible. It looked like a drunk rainbow came over to my tank and puke all in it.