Hi,
thanks for your post, and sorry for the confusion.
No, the plugin does not need to be removed. It is fully working.
However, it will no longer be maintained or developed, as it has an official successor with the name TablePress, by me, the same developer.
TablePress is basically an update to WP-Table Reloaded, but as it has some major changes (some of which might not be backwards compatible automatically), continuing under the same name was not possible.
Please read https://tobias.baethge.com/2013/01/tablepress-replaces-wp-table-reloaded/ for more information and a more thorough explanation.
Migrating from WP-Table Reloaded to TablePress is easy, but no immediate action is necessary. The banner is just an attempt to stop new users from installing WP-Table Reloaded now and then having to make the switch within the next few months. Starting with TablePress is recommended.
Regards,
Tobias
P.S.: Now, I’m not sure why the banner lead you to give a one-star rating for the plugin. All information about this was available and communicated on the plugin page here. I’d appreciate it, if you would reconsider your rating and maybe update it and only base it on the plugin itself. Thank you.