It is in a way for a sort-of new player, but it does get easier, there are guides out there that show you what to expect.
http://www.youtube.com/watch?v=hYVpWGdrVLk
You may get rune armour by going back to Oziach after killing the dragon. He will say that you succeeded and you will finish the quest. You may then buy a rune platebody (or green dragonhide body) from him. You may also buy rune armour from the other players or the Grand Exchange. For a guide on the Dragonslayer Quest: http://gameolosophy.com/games/online/runescape/how-to-do-runescape-dragon-slayer-quest/
You must talk to Galanoth and do his quest and he will level up your DragonSlayer class.
To get dragonslayer you need to do all the quests in the lair (The last quest is not that easy) and you will unlock a shop which has dragonslayer (most dragonslayer skilles are for dragons only) Hope i helped☺
Wizard Mind Bombs I believe is used in the quest "DragonSlayer". Correct me if I'm wrong. It boosts your Magic level for a short period of time.
you need 33 quest points so do the following quests demon slayer shiled of arav vampie slayer etc all of them except for black knights fortress
Yes, you can obtain the Corrupt DragonSlayer armor in AdventureQuest. It is dropped by the Dragonslayer General when you defeat him from the "Confrontation" quest chain.
In my opinoin Its not.... but for some other people it is....
After getting dragon marshal quest completed
No not at all it is just a long quest but worth it.
You could get the Dragonslayer in Aqworlds by completing all quests Og Galanoth in Dragon Lair.
You don't get dragonslayer "exp" you do get DragonSlayer armor skills and lvl ups (armor wise) to do this go to Galonth and do his quests after you have his class set as your main class