I completely understand what you said and how you feel, my server is currently in the exact same position. I'm from S175 and we just merged yesterday with S172 and 178, now bare in mind, before the merge, yes things were annoying because my server fell under the whole "Oh, it's always the same players who win blah blah blah" however, we never missed any events during the week that would be caused by lack of participants, we could still do GNW even though there was only my group in it and we could beat the fox. However, my server only has 2 spenders one of which who quit, S172 and S178 and both massive spenders and have leve 85 players were as we have me as the highest at 83. The BIGGEST confusion here is everyone from those servers stated and I quote "Is this a joke? We had more participants in the fox and Sage battlefields before the merge than we do now"
This merge has literally finished my server of just to give those other servers a more interesting game... so yeah, I completely agree with you, they should merge servers dependent on the BP of those servers and NOT the activity. Our merged server went from 3 servers down to near enough just them 2 servers in one day.
ofc, BP isa better then just age from server, just think, if server 200 have rate BP 50K, 210 have 45k, 220 have 5 ppl with 70k asnd 10 ppl with 53k. while the 240 server has 55 - 62k, then it will only give pleasure to 220.
This game is not based on the level if you want to win a lot of fights, it depends on the initiative, ninjas, magatama, cave, 8 inner gate. others are less important.