change is the status of a religious practice in Fiqh, in religious law, in religion is Biddah.
for example making a sunnah a fard is biddah.
before doing an objection on niaz, kunday, matam, eid e ghadeer, sab e baraat, 21 ramadan etc etc. we must understand what is religious status of these things.
people dont define the status of an act. not even the Imam (or kahalifa) can define the status. this value it only gets from Allah. Allah told us which act is of what importance.
It is objectable if somebody make niaz a fard act, somebody make kunday with Jamat. somebody call for eid e gadeer prayer in the Morning about 7am. etc. since we dont find any of such thing we can t say there are religious amendments.
if people are keeping these things on the same status on which they are , its fine. practicing in greater number or smaller number does not effect the status of a practice. for example if all the people are praying a specific sunnah prayer regularly it does not mean that its fard.
the question about Tarawih, is that its status amended by a Khalifa. and people are stuck, whether they should follow or not?