At the time, it appeared like the right thing to do. McVay needed a WR like DeSean Jackson in Washington the ability to go over the top of the defense and Cooks offered that and more. The Rams traded a first round pick and then signed Cooks to the extension, ensuring the value.
This issue with Cooks is health first, he continues to lower his head to protect himself, which has only increased the number of concussions, which had led to Cooks playing scared last year, prior to the end of the year. The reason this seemed like a good move at the time was, rookie WR's also seem to take time to adjust to the NFL, however, last year three rookies proved to be outstanding for their teams in D.K. Metcalf Hawks) Deebo Samuel (49ers) & A.J. Brown (Titans) and thus, making the move giving up a first round pick proved costly.
IMO, I think the Rams have learned that draft capital, especially with the Cap is crucial, it allows you, if properly utilized to acquire talent, that is not as costly. I do applaud the Rams for trying to take care of players that were crucial in taking them for a lower tier team into the upper echelon of the NFL like Todd Gurley and Gurley was young enough at the time of the extention, however, that knee everybody feared when he was drafted, finally gave out and it is unfortunate, but the Los Angeles Rams will learn from this and move on.
As to extended power for McVay, I believe he already has it. It's a collaborative effort and I do believe in Les Snead and the scouting department that Snead has put together on the college and pro player personnel departments. I did like the Ramsey trade, but moving forward I don't expect these kind of moves and believe the Rams have the right regime and correct power structure to return them on a cusp of another Title for all of Ram Nation, who deserve it.