With the recent lighting update most things have taken a turn for the good. Groundtextures and the landscape itself look more realistic than ever. But I personally can't say the same for most trees that can be found on altis.
Examples:
http://imgur.com/uGVMg3F
http://imgur.com/YBU1NdW
IMHO they look way to bleak and faded as if they are diseased. Tanoa has given us an awesome terrain with very vibrant and lush colours and I get that Altis is more arid and dry but these trees could be a more healthy green!
TLDR: The trees on Altis look bleak/out of place/out of contrast/faded and should be more green and lively.