I am certain most of us would like Tree of Savior to be profitable and stick around for a long time, but the issue is where IMC can make money without upsetting the F2P player-base.
My suggestion is allow us to use TP as a second way to improve attributes. This allows an impatient player to increase their power by a small amount, but still allows the dedicated F2P player the ability to accomplish the same goal without spending money. Just an idea to make some income without upsetting too many people.
Note: I have no issue with any of your other TP services at current, simply recommending this as a supplement.