It’s meant to be a Chompers’ hard counter that’s why its speed is just above most chompers.
If it has to function properly, it has to be boosted on speed and at least on same level in attack and health to compete with chompers, and to be out of range of SI rampage.
However, Since the only meta Chomper right now is Thor and it has instant charge, that means Diplovenator will suffer 2.5X damage from Thor after 1st turn. And even after distraction, it will be in range of Draco unless it’s heavily boosted on health.
At this point it’s better off using sinoceraptor again since it needs less speed boost to outspeed boosted chompers and has armor as well as instant charge itself.
The design of instant charge and SI rampage will always constrain the variety of usable creatures until they are reworked.