First of all, parts of the description of this card are false: Steam Healer has 1800 attack points and 1000 defense points, and is a Level 5 Water Warrior.
I've seen a few other people here try to review their favorite E-Hero fusions, and when I saw someone try to write their review on Steam Healer I figured that the fine people of TCO would like a thorough review by yours truly, since my first 6 E-Hero fusion reviews went over so well ;).
Steam Healer may be the weakest fusion so far with only 1800atk points and 1000def points, but that doesn't make him the least powerful/useful (that title, in my opinion, would have to go to Tempest).
Basically, the only uses Steam Healer has is to increase your lifepoints and/or as a regular Warrior beatstick for E-Heroes. That's about it. Simple.
Strategies and game play:
Being the weaker of the fusions, this guy requires some MASSIVE strategy. In theory (I've never tested this out), you could make a E-Hero/Water deck focused around Bubbleman and his fusions, in which case Steam Healer would be much more powerful than in a straight E-Hero deck. Level Limit Area B/Gravity Bind + Demotion = a LOT of life gain. Demotion would also fit with Sailorman, coming out in Enemy of Justice (I'll get to him when the time is right, guys). Other than this little combo, just use the same strategy you would in any life gain deck or that you use with Flame Wingman.
Combos with other cards:
Riryoku, Fire Princess, A Legendary Ocean...basically, this guy could fit into any Life Gain deck, WATER deck, or Elemental Hero deck.
Ways to counteract it:
Bad Reaction to Simonchi is Steam Healer's main weakness, aside from his incredibly low stats for a fusion monster. Also, since his base stats are so low you could easily wipe him out with a 4-star monster like Luster Dragon.
His life gain effect can come in VERY handy late in the duel. Steam Healer may not be your go-to fusion monster in a regular Elemental Hero deck, but when you need him to re-vitalize your life points, he'll be there to help....it might take a "Miracle", though ;)
His base stats are incredibly weak, and he's not immune to all the monster removal out there. But as long as you treat Steam Healer like any other non-fusion E-Hero in your deck (like Sparkman) and protect him well enough, you should do fine.
In a regular Elemental Hero deck: 4.5/10
Elemental Hero/WATER deck focused on Bubbleman: 8/10