In my opinion:
We need new dinosaurs and weapons!! (even if it's only occasionally, every 2-5 months, not after 10 years!!)
New maps!! (even without adding new levels! For example: Levels 45-50, since most players are around those levels)
New mechanics!! (Like bosses, but they should appear every 5 or 10 levels! (For example, level 5...level 15...level 25...) We also need to include low-level players!!)
Some kind of trading system, please, and make sure it's fair!! (For example, I give you 20 items you need to upgrade a dinosaur to level 51, and you give me 15 items I need to upgrade my weapon to level 52...)
Some kind of PvP tournament system! (Many people are passionate about PvP. Imagine an OFFICIAL tournament in a coliseum or some kind of dedicated PvP area, where, for example, if you win 5 PvP matches in a day, you win 10 gold... Or if you win 100 PvP matches in a week OR a month, 100 gold. It should obviously be balanced, both in terms of rewards and levels, or you could choose your opponent! For example, a board where you can sign up at that moment.)