It's very unlikely that it is "Tomcat" freezing. Tomcat is very reliable and very performant and doesn't have a history of such problems except in cases where Tomcat is either damaged or attempting to run in a severely constrained environment (for example, not enough RAM).
It's much more common that problems like the one you're describing come from one (or more) of the applications deployed within Tomcat. Meaning that the application(s) were poorly designed.
I once inherited an app that took over 20 minutes to come online. The idiot who wrote it made it load practically an entire database into RAM as part of the app startup process. A few changes reduced the Tomcat startup time to about 2 minutes.
Customer surveys are for companies who didn't pay proper attention to begin with.