Your argument about sunflower having both as an excuse to make the scientist more powerful in the second game is pointless, this isn't about the first game, it is about the second which both sunflower and scientist have both healing tools, so giving the scientist the faster healing station option while still letting him use the heal beam will make his healing so much better. Just because you don't like the heal beam doesn't mean it isn't there, you can't buff the other heal options because of people who don't want to use it, especially if both are usable at the same time.

The cheetah healing station made the scientist's healing so much better than the sunflower, it isn't an opinion. When you take into the consideration that a scientist's cheetah station can heal him from 1 hp to full almost instantly (while still healing his teamates also standing next to it) where as the sunflower has to sit around for ages to heal the same amount and even longer when her teamates are nearby to get healed by it as well.

For a single heal flower to fully heal the entire plant team to full from near death the cheetah station (even the plain ol slow heal station) could fully heal the entire zombie team several times over, throw in the scientist heal grenade it would make the time to fully heal the team beyond silly. Hell, the heal flower barely lasts long enough to fully heal a couple people, even when not being attacked. The only thing that kept it remotely balanced was the fact the sunflower could heal on the fly with the heal beam which still doesn't compare to the sheer speed the cheetah station could heal people.

Now that zombies and plants can both attack and defend they need to be far more balanced and giving the scientist the absolute best healing tool ON TOP of the heal beam, it would absolutely destroy the game's balance.