Is it just me 또는 did chapter 420 make it sound like Bleach is really coming to and end after the defeat Aizen?

yes, it did sound like that, but ourmanga.com has up to 20 some odd extra bleach files containing chapters that go up to 443. there's still an epic battle to take place and explinations to be told.
yes it did sound pretty bad that ichigo would loose all his shinigami powers, but he'd still have his hollow powers, and isshin even said that his own zanpakuto didn't want him to learn the final 옮기기 either...which is how isshin 로스트 his powers, but he had gotten them back 20 years later...
if ichigo truely does loose his powers, he'll get them back, like isshin. ichigo turned 10 years into 3 days for bankai, he can turn 20 years into a lot less!
but no, we still have 20 chapters so far and is increasing...no worries! :)