There is no reason to rush anyway, E50 Set will be the best for a long time(there will be new sets but more like easier to get and a little weaker than E50) and EU version will take longer to get new patches/updates.
I play casual myself and AP income isn´t that bad for me(and i don´t even do raids until now). Get better gear and you can duo or 4ppl abyss chambers(there is also way to do the chamber occopied by enemy faction daily) that alone makes a difference. Go daily dred and do ap repeatables in abyss always moving in a group. Don´t move solo in abyss to avoid ap loss. While building groups you can always farm kinah in brusthonin(or the ely map) where no enemy can disturb or kill you.
While leveling maybe is faster than in the original back then, the rest is pretty much the same. It´s a very long term game and classic will get completely different and new content than the original or live. Like the new class, new unique skills for each class and new dungeons. There will be also patches with content we already know from the past like the enhanced flight which got deleted later again in the original(and for classic we propably keep it this time) but classic goes in a complete different direction than any other aion version.
As for kinah, like mentioned look for the good brusthonin(oe the elyos equivalent) farm spots on youtube, that together with clearing mobs in abyss chambers, dred, alquimia and optional on all other instances(hard to do though as most people rush shait) it gives you really good kinah even as a casual. You don´t have to buy scrolls for all that, except maybe for pvp in dred. All you have to buy here and there for pve/farming is potions which are relative cheap.