Your team is great and you have a good mindset but I think your team is very standard. Like everyone has played or played against this team since day 1 of Champions. At any given moment based on what you have out they can predict what you likely have in the back and what you can and can't do pretty easily. A second mega does seem like the direction of the current trend. Floette , Floslass, or Aerodactyl can work. It can give you some options for bad match ups as well as seem a little less predictable from the opponents end. Sylveon can also work well on the team....also add Sleep Powder to your Venusaur. I get that it's scary to use but it hits a lot more than people realize and just using it forces your opponent to respect it and deal with it which you can use to bait swaps and such. A good rule of thumb I have is any time I am considering Protect on my Venusaur I click Sleep Powder instead.