Reducing the cost for all STATICCALL is not a good idea. There is a vector attack (exploited in Changai attacks) that allows to make multiple calls to multiple contracts forcing the client to search and load the code from the disk of the clients. That is why this cost was incremented at that time.
According to the core devs meeting, it is more easy to define a new code that to touch the acutual call code of the clients. That is why I refactor the full EIP and created a new opcode.