I have a flysky i6 which came with a fs-i6a. Its been great but i know now its the very bottom of the top. I know also my rceiver is very limited to not much for than flight. No ppm amongst other things. What i want to know from my friends here is where do i go from here?
The answer to that last single question is a question: what do you want to do? (If you want PPM get nothing more than a $15 PWM-PPM converter.)
90% of what you will probably do further with multis is done in the FC not the TX.
What do you want to do 'more than flight?' Flight requires pitch, roll, yaw and throttle. Two more channels on a two and a 3 position switch give you six flight modes.
For tuning rather than flight modes copy the 'flying' model that you're working on to another model, and reprogram those channels to sliders to do OpTune or whatever. Again, the info gained from OpTuning is programmed back into the FC not the Tx. Then change the aircraft's bind back to the 'flying' model in the Tx and off you go.
I got started with fixed wings. Six years ago I got Futaba 8FG. Only one plane I've had so far uses all eight channels. Even that I could have done with 6 but the 8 gae me more variability for the application I needed. Then later a firmware upgrade kicked the channels up to 14. No multirotor needs 14 channels.
I have no plans or needs to get another Tx because I started at the top.
Do you fly with other people who have other radios? Or go to a hobby shop and ask to handle a couple of them. The 'feel' difference between various $400, $200 and $100 radios is the difference between upholstery leather, cloth, and plastic. Personally I prefer leather.
Besides 'feel' the only other real difference between radio 'levels' is model memory. The 20 in your Flysky is a bunch. The 8FG has an SD card which means essentially unlimited models, though I doubt I'll ever have that many.
I *do* use a lot of models, many times 2 or 3 per vehicle to try different configs. I do that because it's easy and I -can- do it, not because it's necessary.