I think the Devs were worried that making the created angels bigger could create bullpuffy Levels of buffing, but with Harahel now as a Champion, the OS have lost a good deal of sharpness to their claws.
I do think the Champion mechanic is very interesting and getting more ways to use it would be good. Currently switching Champions and fun and all, but it is not only slow and hard to do, but it is also quite expensive. Even with the cost lowered by Herald, I still have Trouble making it work.
And there is also the single fact that with the new Champions, the OS are overfilled with 4-drops, since all but one Champion I have seen is a 4 Drop. In Addition there are Cards like Cheryl which makes me wonder what to do with them. OS aren't supposed to be alone. Kali and Lucca Ascended are also 4 Drops, same for Xi, Ascended with her crazy ability.
Also, although gaining a vanilla 2 drop with the recent hotfix, they lost their only vanilla 3 drop in Grounded Angel.
They got a great 5 cost Card in Heavenly Wish though.