@TheSprinter85 I think a good work around is to give every class a alt ability that allows them to get to higher ground.
I remember someone suggested a grappling hook for chomper where you would have to aim of course but it would pull him to the area he hits. This way it requires skill since you have to position yourself at any angle before using it.
Of course in using this for mobility chomper would have to give up one of his abilities thats so effective on the ground.
Sunflower could give up heal flowers for an umbrella leaf from pvz 1 that launches any plant that jumps on it into the air at super pea jump height. This way its still tactical and can still benefit the team even without healing. Maybe a cool idea would be that it could also launch away long bombs that land on it like the 2d games.
Cactus and deadbeard can freely swap between wallnuts and cannons for alarcity and anchors away. This will benefit different playstyles.
Imp could lose impkata or gravity grenades for an ability that launches his boosters into overdrive causing him to fly upwards if you hold the jump button for a time.
All these ways would allow other classes to catch up but not exactly match the vertical focused classes. That classes like chomper arent left behind on maps like main street or zomburbia but dont become a new tyrant of the heights since they would have to take way something in return so sunflower couldnt just jump to the heavens plant a heal flower than rain sunbeam death from above with little challenge.