Quote from Ailyene;560065:
Well, I was comparing Rain Casting to Life Drain and Heat Buster. Rain Casting doesn't take a ton more than LD (about 50 more or so) and Heat Buster takes more AP than either of them, so it seemed kind of strange. But since it's a theory, it could be off.
Rain Casting however has much higher out-of-combat applications than Life Drain has in-combat. Its influence on alchemy and life skill production is tremendous. And then it has the added (although niche) benefit of improving Water Cannon and hitting enemies for miniscule damage. It's a very powerful skill, but not in the conventional sense (where we'd only be talking about combat applications).
To give a better idea, let's consider something like Rain Casting versus something like Carpentry. Carpentry is a premiere skill for meleers and people interested in crafting bows, but outside of that, people would hardly touch it. It has no immediate combat applications, after all, save for stat gains and possible weapon creation. Rain Casting has very minor combat applications, but influences many skills that have indirect combat purposes (life skills, Synth, Metal Conversion, and Frag) and even one skill that has direct combat purpose (Water Cannon). It allows you to bring a T-Storm with you wherever you go (save for cooldown and cloud crystals), thereby bypassing the weather system that this game's production revolves around. I've also heard it can stack with actual in-game weather (T-storm squared, perhaps?). That coupled with its high AP cost makes it an extremely vital skill to learn for any crafter/archer and a true testament of someone who's not just dabbling in alchemy (a show of dedication and mastery of all things alchemist).
Shock's bonus hails from it being expensive, powerful,
and hard to get. Not to mention having one of the most powerful titles for any type of combat in the game. Life Drain's bonus hails from it being expensive, flexible, and moderately powerful despite its multitasking ability (healing and damaging, where it does surprisingly well in both); its greatest power, however, is its ability to bypass a LOT of defensive stats and abilities for full damage, where at least one of its functions (drain and/or knockback) will do their full damage. Flame Burst gives Alchemists one of their few control-by-damage options besides Shock, Sand Burst (which is weak and limited), and Wind Blast (which is weak). Unlike Barrier Spikes, it actually controls by doing damage, and unlike Water Cannon, it damages and controls multiple targets simultaneously. For that reason, it has a higher bonus than WC, SB, and WB. Frozen Blast is expensive and can be shaped into one of alchemy's single strongest control abilities, not only manipulating a bunch of enemies simultaneously, but tenderizing them for more powerful attacks from other abilities as well. For a long time. Heat Buster is powerful and expensive but severely limited, more so than Life Drain. Much more so.