Super bean

I think super bean is only bad on crazy mode. His beams deal way too much damage but i find the yeti far worse.
The yeti slows you down with every hit (which he never misses with) and he deals a lot of damage and moves super fast. Getting a super yeti wave is the worst as well since not only are you spammed with multiple yeti's but also frost zombie variants. you have no chance to do anything once you are slowed and inevitability frozen which always leads to death. i've only been able to clear a super yeti wave once and it's just impossible to clear on crazy difficulty

SuperBean isn't actually all that bad.

Handling two or three at once used to be a terrible grind but they reduced the frequency of him going into OverBean, that screeching energy beam mode with the massive damage reduction, and since they did that he's not any more or less a pain in the butt than any of the other Plant Bosses. Sure the teleportation is annoying but the Zombies have Baron Von Bats who does the same thing, only he gets to Heal every time he sneaks up and smacks you a good one instead of summoning a Shield like SuperBean.

Super Bean is easy to take out.  #1 Have at least one scientist who heals. The scientist must keep you and you bots all healed up.  #2 Plants bots and let them assist you.  The bots can do a lot of damage for you if you allow them to.  I let Mr. Freezy beat up Super Bean all the time. Stop letting your bots go to waste. Use them!  #3 Spread out!  Don't all attack from the same place.  Each player attack from all sides.  You will have players and bots attacking from all directions.  This makes it so easy to take him out.  Bonus! #4 Toxic Super Brainz.  Give me 1 scientist behind me and I will easily take out 3 Super Beans.  Follow these steps and you will have no problem with Super Beans again.  

In my opinion the Yeti Zombie is more OP than the Super Bean.

The Yeti is a real pain because of that super quick scamper that he does, unless he corners himself or stops to summon hail he's hard to hit with most characters. A Chomper's Goop attack is awesome for countering his speed and erratic movement but the catch-22 there is getting close enough with a Chomper to hurt him means that you'll get yourself frozen and then off he goes again.

I totally agree with you. It  will be more reasonable that the same variant character should have  ah.. Something like protection . For example, centurian (fire soldier)  is taken less damaged by BBQ corn or fire chomper. And also power character. That will make the game more interesting!