Hi! I hope you are doing well!
So, I was looking for guilds as well, and I have stumbled upon your post. More I read the about guilds, I have noticed couple / few things they have in common, so I would like to share with you- I bet you have noticed wayyyy more than me though… hahahaha … ;;;
- Limitation on numbers - Looks like Guild(s) have the limitation of how many members in the guild- I am guessing about 30-35 people? (as it seems that way)- so the competition of joining might be fairly difficult.
- Guild have fears! - Guilds just like the whole game itself have fear of people leaving… So, they want someone who will play long-term, not just play for few months and leave.
- Dedication - Looks like guild(s) wants member(s) already dedicated in the game per point #2, and further guild itself- This means that someone who has higher ranking. (generally rank 5+ seems to have easier time to getting into the guild than below rank 5).
- Guild goals / Pride- Looks like guild(s) have some goals either win GVG or PVP… or etc etc, and Pride of what they do.
- Personality / Language / Meeting - This is always exciting part of the guild to meet someone new and get to know someone! However, this also means that the guild itself is risking the issue of having possible guild dramas… hahaha Because not everyone can get along… SO! although we (I consider myself a newb…hahaha), newbie, applies since they don’t even know much about us and low on lvls and rank lvls, it is unlikely to join… hahaha
I do apologize for making longggggg sentences… BUT! time is on our side! more time you spend on ToS - You will gain more levels and get to know in-game people - then, easier to join the guild!! xD
As of today (01/09/17)- I just made lvl 178 rank 6 (Cleric C2, Priest C3, Krivs C1) - Soon to be PD C2… (hopefully). - Just like you, I love supporting / Healing / Buff. Other people can have glory of monster kills xP For me as long as group enjoys dungeon and clears at ease, my goal is done hahaha - But, being Rank 6 (I am going to wait at least I am class lvl 10 ish), so I can try to re-apply for the guild 
I really wish you good luck!!
And sorry, if this post gotten wayyyy wayyy too too long… T.T (It wasn’t my intention) hahahaha