Yep. Gohan is a wild card, the thought that his power is anything like the others probably isn't very logical. Just because he's gotten really strong and attained 2 Super Saiyan transformations shouldn't make us forget about the wild card issue with him. As we see, Gohan is massively, massively superior to Vegeta and Gohan when his full power is brought out and pushed way beyond. Gohan's latent power is pretty much the biggest deal in the whole manga. He is pretty much the manga version of Broly.
Also, it still doesn't explain Goku's quote either. Goku's Super Saiyan 2 had already been exposed. Vegeta instantly figured it to be stronger than Gohan was at Cell.
The fact that Gohan's power was still relevant to a 7 year trained Vegeta with a Majin boost seems to suggest that something else was going on. Gohan never appeared this overwhelmingly strong at the Cell Games prior to his Super Saiyan 2 transformation.
His Super Saiyan is stronger than Goku for sure, but it isn't disgustingly more powerful. Vegeta trained for 7 years and is still nowhere close, yet thinks Gohan is complete trash at his current level.