I presume the slow progress is to force players to pay more money.
Paying money gives you exactly 0 exp.
Well that is certainly not true. Look at your Siels Energy icon when it's grey compared to when you have paid, there is a vast XP rate difference. Also there are a whole bunch of quests for XP you can't do without Siels Energy because they require you to loot quest items, even simple things like keys in KT or Theo labs. Also you can't roll on drops in a group. So paying money gives you access to a lot more XP.
That said, I am going back to playing only 1 hr per day until they fix the horrific XP rate here, I have renewed my sub on the NA servers in the meantime.