Wordpress Hosting is a misleading term. 99% of the time, it is plain LAMP hosting. In wordpress will be fine on most shared hosting. Server optimization for Wp doesnt really matter, what matters is how well they take care of the server itself. Unless the host offer specific services like Wordpress customization, theme / plugin instllation, upgrades etc (not using any script installer), dont even think about paying extra for a specilized Wp host.