Schiff is basically floating a trial balloon to see if they should go ahead and push for impeachment. It has almost nothing to do with what Trump has done, purely political. Obviously, since the Democrats were talking impeachment from the day after they were hurt so badly in the election, it has nothing to do with anything Trump did, other than beating Hillary.
It's all about the Democrats grasping for power. They see Trump is an outsider, so besides their hate for any Republican President, they know that many Republicans, steeped in the establishment like them, will not oppose them. Regardless of being in the majority or minority, it's a good, cushy, rich life for those guys, on our dime. The last thing they want is someone like Trump, who upsets their life in the bubble.
But there is also a lot of risk and danger in failing. Trump is very good at defending himself and making these politicians look like the corrupt fools that they are. They know they are vulnerable. They MUST have support from the American people to go forward. But, they could lose it at any time during the process, and then they are toast.
So, we have the trial balloon. But they need more than that. Way more.