One more point that has come to my mind which BB should consider:
Most players will probably consider buying the weekly membership in the key holidays since that will permit them to reap maximum benefits.
They will be storing up their most valuable adventures for their vacation, then crunch adventure after adventure as quickly as possible.
While in the past, players also adventured stronger than normal during holidays than off-season, people still did most of their adventures "on the go" while simply being a bit more active during holidays.
Also, in the past, players have simply come to accept the bad latency making people unable to successfully run complex blocks on adventures because "well, it's just like that". But when you have been storing up adventures, waiting for vacation and paying for the rewards, I doubt you'll be accepting that easily to be screwed over double because of lag.
Two effects will come into play that BB should consider very carefully:
- significantly increased server load on holiday peaks due to significantly increased amount of adventures engaged by paying players
- significantly reduced level of tolerance for latency and zone crashes on adventures engaged by paying players
In combination, Bluebyte must be aware that the Premium Account is not additional free money but requires both significantly increased server capacity as well as administrative activity (load: balancing, testing, monitoring & support) around this increased capacitiy which people have previously tolerated at a - well, "below industry standards" level, which they will no longer accept once they "pay premium".
Please, Bluebyte, tell me that you have calculated this business case carefully, because to me it looks like marketing still has to catch up some loose ends here and there.