I'm not going to bash anyone, or contradict what anyone says. Everyone is entitled to their opinion. Believe me, when I worked as an English teacher, I saw some teachers that made my hair curl.
But in the defense of Eikaiwa teachers:
While there are those people who go in, and are speaking partners for Japanese people who can alrady speak Japanese, these are the minority. My friend recently started working for Shimon Juku after a long stint with JET and Interact working in Junior High Schools, and he says that it's the hardest job he's had in Japan. He also said he would punch any JET that complained about their workload.
This is his situation, so it may be different for other people/schools, but:
He has to make all his own work plans, over a month in advance for classes that range from 3 year olds to 16 year olds. Sometimes he has classes of one student, and sometimes classes of up to 12. If only one student shows up that day, he has to re-arrange his entire plan to fit that student. This may not seem hard, but keep in mind that for very young students, you can go through 10-20 games in a one hour period. If the students lose interest, you have to go on to the next one right away.
When he works, he is not allowed to use Japanese. Shimon Juku is very strict about all English. The downside to this is getting the smaller children to do what you want without a) using a language they understand b) losing their interest and c) killing them.
Lastly, because it's a Juku, his work schedule is based around when students are available. That means 12am to 8 at night. And usually that's straight classes, with only a 5-10 minute break in between.
Anyhow, he's been complaining about how busy hs is lately, so I thought I'd just share his experiences.
I don't think that they're representative of the English teaching profession as a whole, but I think there are alot of people who work very hard as English teachers, even if they're often surrounded by one-year drivel.
Which is why I say "Hate the person, not the occupation."