It seems like even when a church has a good Pastor, the church as a whole can leave its first love.
A number of historians have concluded that John had served as the Pastor of the church in Ephesus for a while.
So, then considering what Jesus said to that church, how they had left their first love, was not because of their Pastor.
That is why I've always believed that the seven angels in Revelation 2 & 3 are just that, the angels of those churches, like it says.
I do not think that Jesus is writing simply to the seven Pastors of those churches, since some Pastors had gone home to be with the LORD.
Other Pastors then were called by the LORD, and they eventually left or died too.
However, the churches continued, as would angels, they don't die when the Pastors die.

The problems of a church are not simply due to their Pastor.
I don't remember the Apostle Paul rebuking the Pastor of the church in Corinth, but he did rebuke the church.

So, even though they may have had Pastors in Ephesus like Timothy & John, the church of Ephesus collectively still left their first love.

I don't think that the problem was with the previous Pastors, or even with the Pastor that they had when John was on Patmos.
It would seem that it was more likely a problem with the church of Ephesus as a whole.
                         Gino