Hey guys, I'm new to board games, for sometime I have been watching elder sign and it got me interested, so I was about to buy the base game and unseen forces (I think it add more stuff) and replace some cards from the base game (not sure about that), but I just went to check for the game to order and saw the store are taking preorders for the new gates of arkham expansion, and (I'm not sure about this) but from what I have seen there are lots of cards (or full decks or maybe missions deck?) that are going to be replaced? my English is my second language so I'm not sure if I read that information right or wrong.
So my question is which expansion packs I need? do I need the base game and both expansions? or which box to buy? I'm looking to buy everything there is to the game that adds more variety at one time and combine everything to have the updated game with the most variety in missions, however I don't care about the variety in characters or enemies (for example if gates of arkham make unseen forces expansion only useful for the characters it have or monster cards then I will avoid unseen forces unless it have some very important replacements that need to replace some important cards in the game), as based on what I have seen so far the base game come with lots of characters and monsters, so I'm only looking for more missions variety or new stuff to do. So based on that which expansions I need to buy or avoid? also if it have any effect to it, I'm only going to play solo.
I'm sorry if this question have been asked before but with my English is not perfect yet, it's kind of hard for me to search for older topics xD .