SuntanIronMan: If you purchased the Game of the Year (GOTY) Edition, then you have all of the expansion packs. All the expansion packs are included with your GOTY Edition purchase. So you have everything and there is nothing else you need to purchase.
The expansion packs are for people who do not have the GOTY Edition. If you have the base game-only, then you need to purchase the expansion packs to play the additional content. If you have the base game and then purchase all the expansion packs, you will have the same content as the GOTY Edition. GOTY Edition = Base Game + Expansion Packs.
I hope that explanation helps.
You forgot one big thing too, The menu system on the original and game of the year are different by large.
when you are adding those runes to make your attacks better and give abilities it's like a whole new ball game from the 2 versions I have. I have to say the original with expansions is far better and cleaner then the Game of the year additions menu.
Raynys: As title, i bought the base game times ago and i've seen there is a new GOTY edition. So, there is some upgrade pack to GOTY or i must buy all DLC separately???
Stick with the original and the expansions, Go look online to see the difference in the item menu and see which ones is better for you. the original feels nice and some love the new version from the game of the year. it's all personal opinion.