I'm afraid that I'm not actively doing Tomcat development at the moment, since the people who employed me to do that are seriously in arrears regarding payment, but the story is that if you search the Eclipse Marketplace (In the Eclipse Help menu) and look for "Eclipse Tomcat Plugin 9.1.0" you'll find something equivalent.
WTP is an abomination that seriously mangles Tomcat's internal operations, which is why I avoid it even though it comes pre-installed. The sysdeo/mongrel plugin did require you to install a stand-alone copy of Tomcat (actually, so does WTP, IIRC), but you then configure and maintain Tomcat directly, just like you would on an IDE-free production server. WTP makes imperfect copies of configuration information and uses that, which is why I despise it so much.
You've always been able to hot-deploy (and re-deploy) webapps in Tomcat. The problems came from 2 sources: 1) versions of the JVM that used PermGen storage wouldn't release old PermGen space (which was a major issue for apps using Hibernate, for example). And static classes tended not to re-initialize when then new version of the app loaded.
PermGen went away with
Java 8, but I don't know what, if any progress has been made on ensuring that the new app load acts totally clean in static resources.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.