The terrestrial part is a waste of volume...and i also think it's a matter of time before that depth of substrate starts being a problem. Furthermore, it is complete useless as it appears in the picture as it is way too dry to be used by the newts at all. It's just taking up space.
The newts would be perfectly fine with a piece of cork bark, which they are unlikely to use for any significant length of time.
I would also say the tank needs a lot more plants...A LOT, and variety is always a good idea. Anubias grow so slowly that they are very inefficient.
Is it just me or are there two different species of newt in there?