I don't mean to sound condescending here but, you are. I can't tell you how because I haven't seen you play, but I have done numerous L10-L11 2-Man Esseles runs with just about every combo possible. It is not an easy instance with 2 people, but it is doable.
This is actually my point. If an instance is recommended for two people, then it should be more than just doable, especially in low levels.
There are always going to be people who can get just the right combination of powers and class sets, or do exactly the right fight, to do things that are beyond what is recommended, ie soloing an instance that is recommended for 2-4 players. This will always be the case. However, if the instance is designed for two players, is a low level intro to instances, it is reasonable to expect that two people, new to the game, should be able to do it. Chamber of Speech is a prime example. Recommended two players, it is doable with one but difficult. Two people and it's more than doable. The case should be the same for Esseles. It should be doable by some solo, more than doable with two.
Just because you found it easy, does not mean the instance is balanced for everyone. Which it should be for an low level introduction to the first real instance. The expectation should not be so high as to compare to a high level raid in regards to being unforgiving to new players.