User blog comment:Flamesword300/Overlooked? Ichigos true strength/zanpakuto discussion/@comment-5681812-20130621063411/@comment-11051098-20130621142817

When he faced Aizen in the real Karakura Town in the SS, Aizen stated that the reason he couldn't feel any reiatsu from Ichigo, was that Ichigo discarded all of it for the power he needed to defeat Aizen. It seems it was not that his reiatsu was too high for anyone of Lieutenant level to feel, he simply discarded it for more power.

Concerning powers, I think he should at least learn to use Blut and Blut Vene, and it would be awesome if he also learned to use Hollow techniques like Sonido, Cero and Bala. It should be possible, as Hollow Ichigo is his true Zanpakutô, and Hollow Ichigo used Sonido and Cero against Ulquiorra.