In contrast to you, I am satisfied with the current interface because I like the dark mode with little light so as not to dazzle. Anyway, Tengricrypto.com is a site to mix BTC, not a place for entertainment.
The fact that it deals with serious things like coin mixing is all the more reason for the interface to be adapted to the user experience basics of web design. I have nothing against dark mode, I am just pointing out that it needs to be more readable.
This is a very young mixer and there is plenty of room for improvements.
I also loved the dark mode, but the text input field was a little unsophisticated, I just a thought if the team would make that better in the future, I also found at the bottom that they give the heading as Bitcointalk but give the ANN link of Altcointalk instead of Bitcointalk. I hope that will be improved soon.
Since ETH is also a famous coins and mixing of it is very needed, I guess the altcoin lovers will give more priority to ETH mixing when it gets online.
That depends on the requirements of the users whether they prefer privacy or not, if they do then it is not a hard task to acquire privacy so it doesn't really matter that much altcoin lovers will give more priority to this service. It's just a thought but the real functionality is what will attract them and make them love this feature. Till then we should wait.