the issue with concentrate mining power is still existent. it has to be solved and not with just an appeal to the miners. it has to be fixed within the code.
Miners still receive a large portion of their block rewards as block subsidies (the 25 BTC that every found block receives) so as of now the risk of a 51% attack is low.
As the percentage of TX fees of the total block rewards increases the incentive to attempt to launch a 51% attack will increase.
In short, the risk of a 51% attack is low now, but is an issue that must be dealt with as the threat will be real in the future.