Things you are ignoring:
1. HP boost due to Attribute System readded
2. MP boost (making cure penality not much of an issue)
3. MND healing boost
You do not need to AOE cure at all pre 30, hell barely ever past that. I never have Curaga on my bar, never needed it at all. It just caused way to much hate so it was pointless to me, i was much faster at cure 2'ing. Pre 30 you dont want that hate.
All the content pre 30.. even 40 is designed for 4 people, 1 being you. Do you seriously need an AOE heal for 3 people?
20% of the levelling curve goes quick, even for new players it will go quick, but that isnt the point because new players will be brought up with this system and be known by it. You see how new players didnt bitch about cure costs and mp issues, only existing players did because they got used to 1 system and it complately changed.
This is happening now, a player used to 1 system, being told to play in a different way.
Level 30 is not near level cap at all, as said its 20% so that is why people are saying to not worry about the levels as they go quick because the OP thinks he is "almost near level cap" at 30.
Not to mention the current AOE is not always a cheaper, better solution. You might hit it, miss people, or heal people for 200 each, when they need 800 healed, it becomes pointless in many situations. Be more skilled and control your heals better, this will make mp consumption easier.
iirc you can put cure on Thm so...