First, the bill almost certainly will immediately be referred to the Judiciary Committee where it will die. Second, even if it got out of Committee and was voted on by the House and even if it passed the House, it won't get voted on or make it through the Senate. And if it somehow made it through the House and Senate, Trump would veto it.
Leaving all that aside, the bigger problem is that in the end, it doesn't resolve the principal weakness in the 25th amendment -- one that could only be cured by a Constitutional amendment. And that is the fact that even if this Commission was created and it concluded Trump was incapacitated to the point that they could not discharge the powers and duties of the presidency, under the language of the 25th amendment, Trump could dispute that finding and it then would require a 2/3 vote of both the House and the Senate to remove Trump. And that isn't happening.
Nevertheless, Raskin's bill is worthwhile insofar as it highlights Trump's nuttiness. But the reality is, notwithstanding what some pundits claim, the 25th amendment was not designed for the situation presented by Trump's behavior. It was principally designed to deal with the circumstance where the president is unable to act, not when the president acts stupidly. It was intended to deal with the situation where a president is unconscious, either for surgery or due to illness, or is otherwise unable to make decisions. Trump can and does discharge the duties and powers of the office -- he can and does sign legislation, make nominations and appointments, dictate foreign policy, etc etc. The solution under the Constitution when a president exercises those powers badly or even irrationally, is through elections, unless the actions not only are irrational but constitute the type of action that should be addressed by impeachment, such as committing or threatening to commit war crimes -- and impeachment is a lower bar than the 25th amendment.
But, as noted, I have no objection to Raskin and other putting forward the bill as a way to highlight Trump's craziness. But it isn't going to change anything directly.