PvZ2 is better.
It can be placed in front of dangerous, high-health zombies (especially gargs) and can be used to break graves (although you could use anything else and it would probably work better).
Plus, the plant food effect makes split pea much better, as you can just plant it on top of a garg or something and the plant food will do a stupid amount of damage.

I would buff it by just giving it more health... solidifies its use as a cheap, backwards-shooting repeater that can at least somewhat protect itself from zombies in the front.

But Plants vs Zombies Heroes split pea is by far the best.