Well, of course Wordpress and Wix will not be good replacements for iWeb, because they are just not the same - Wordpress is what is known as a Content Management System and you can install it on your server - Wordpress.org or use the free Wordpress.com. Wix is not the same as you create it online and use the Wix servers to publish the site - it is mainly for folks who want a quick and easy option to get a site up online and who do not really know that much about web design or sites.
The best alternative to iWeb will be EverWeb and it was designed with iWeb in mind and to be a direct replacement for it. Take a look again and it has come a long way since the days when it was called EasyWeb - it has not been called that for quite sometime now - being EverWeb - take a look here at EverWeb.
If you don't like the other alternatives, then you can take a look at Freeway Pro or Express and see if this suits your needs.
Other than that - I am afraid that this is what is going to happen with iWeb - it will become less workable with every OSX update that comes out, so it might well be that when OSX Sierra comes out, it will stop working altogether.
Not shame on Apple - look at the reasons that they did it and they have let other software companies develop better applications - iWeb served a purpose, but had a lot missing from it and there are now better applications out there.
Either downgrade your OSX back to where iWeb will work or it is time to move on and find another application that you do like - there are plenty out there. Also take a look at Adobe Muse.