There's just too many pokemon in it. A good fusion is two or three pokemon. You don't want it so fused that you can barely at all tell what's in the fusion, you know?
They look cool. I could even believe them for being a real Pokemon. What you should do is come up with a moveset and information about your Pokemon to give it a background.
Fusions can have as many Pokemon in them as needed. However if you really mix and match you can create a fusion of 10 or so that looks like an entirely new pokemon all together, those are sometimes reffered to as splices.
I will explain cluttered a little more in the sake of reviving spriting.
This is a fusion I did, you can tell you can clearly see all the pokemon that are contributing to the fusion yet you don't have to squint to do so.
You can see that your "base" Pokemon is Garchomp and here mine is Blastoise. In this case the bigger the better, as you have more room to change and expand.
I hope this clears a few things up and I wish you the best of luck in the future.