I don't believe Trump should be impeached over this even if he did seek to get investigations going to root out corruption with Ukraine or even China because it's evident that Trump didn't intend to break the law but was only interested in rooting out corruption and from what I've read there was an agreement between Clinton and Ukraine that said each could/would work to help stomp out corruption.
The precedent has already been set and the only way that a Government official, President or Presidential candidate should be indicted and tried is if there was intent to break the law. That means no obstruction of justice, no problem with private email servers or no problem with Hunter Biden because none of these people intended to break the law. Isn't that the way it goes in the "new" Washington environment?