I think it's really a shame if Yulia has totally busted her voice and can't sing properly anymore let alone scream in the songs - which was a trademark in the Tatu style. But I think it's a little harsh to compare a totally professional show like Lena's - where her voice also seems to be a little augmented technically - to what looked like an impromptu karaoke style performance captured on very poor quality media. ( was that really a "proper" concert? )
The material that Lena is singing is pretty good but it's a deviation from Tatu into a more mainstream pop/rock domain, whereas if there was any hope that some of the old vibe of Tatu would be retained that would have to certainly come from Julia. She was in essence the voice of Tatu - singing in most of the choruses either alone or with Lena - and the screaming was trademark. If there is still an opportunity she should try to fix her voice otherwise her career might be cut short.
Lena on the other hand is very serious about her career and is improving in her live shows, her band looks more tight than before although some of the new songs are ok-ish but nothing that would blow me away. Waiting to listen to the full album whenever it's released to have a more rounded opinion of it. It's more to do with her charisma as a singer that can carry these songs but as I said they don't remind me of Tatu at all.
Now about Julia's looks, she was the hottest little thing on the Prostie Dvizheniya video but I don't think either that she will turn into a parsnip by 2020.
It's her voice she has to work on, if she can. Her song is ok.
And these are my two cents on their solo careers for now. I wish we could turn back the clock and Shapovalov would find a way to make a sophomore album that would be equal - if not better - than the first one. If I had a time machine I'd certainly do that. For now lets enjoy what they can give us -mostly from Lena.
As for the theme of Julia's vid, yes, a little deja vu but somebody has to remind us of the old times. ( wasn't kissing a black guy though in the old videos, was she? )