8-players group as the main core to chase content- fail

[Onyxys]

Greetings. I play FFarr from the pre-order and from time to time am asking myself- why developers made full raid as the necessity for main content and the main const-party formation? Why didnt they think about simple problems players will face?
1) Very hard to find 8 players with same prime-time
2) Very hard to find 8 players with same skill level- to make const-party without "Wagon"
3) 8-players group- very high chance, that someone will not come in prime time and it is a problem, because making replacement for single run with someone from aside is not a good variant- this player can just take loot- loot will get away from const-party
4) Even big clans with daily online 50-70 people can consist of very little amount of const-parties

And if we stack at least 3 first reasons it is very hard to play FFarr if you want to have good progress. Yes, I think it is a fail to make 8-players group as the main group to make const-parties and chase through main content. And this is one of the biggest reasons why players leave the game. Am asking developers to change content, to make 4-5 parties (to create new 5-players formation, for example) as the main groups for content and creating const-parties. Thank you

Addition 1. Dont be mistaken while discussing my post. Im talking not about raid for many people, when the whole clan goes to raid. Im talking about const-party and high end content for const-party. 8 players- it is too much for regular const party
Addition 2Raid dungeon in FFarr- is CT. Raid dungeon (in my opinion) is a kind of dungeon, where mistakes of some players are not visible. You can agree, that in CT 1/3 of players can just stay and do nothing (I'm not talking about pushing buttons- it is very simple)- other 2/3 players will do all the job. And yes, in such kind of RAID you can take any player- very easy to find. But I repeat, that my 1st post was about main content dungeons, first of all high-end hard core dungeons where mistake of just one player very often means wipe. Such dungeons (and trials) are not raid dungeons (CT is a raid dungeon)- they are CONST-PARTY dungeons (I hope you all know what is const-party). All I want to say- 8-player group is too big formation for stable party- const-party. It is a biggest SE's mistake to make such big formation for const-parties to chase content
Addition 3

8 man content is anti guild. There is nothing wrong with it buy it should not be a primary focus. It is no where near enough people. A mmo should be guild based at endgame... 8man everything makes that near impossible.