Hi there and welcome back to WoW!
I’m not 100% sure what you’re looking for, but I’ll tell you what we can offer, and you can see if it matches what you’re after.
Firstly, we’re obviously on a different realm to you … we’re on the joint realms of Lightbringer/Mazrigos. We are Horde, and we are an 18+ guild that raids casually, twice a week.
Having said “casually” … I’m not sure what you mean by “semi-casual”.
We raid Wednesday and Friday, 9.30pm to midnight server time. We’re currently running Normal Dazar’alor, hoping to clear it in the next few raids being at 8/9 at the moment having done a fresh run each week up until now for gear.
Within the next few weeks, we’re hoping to start on Heroic, with the intention of still continuing normal runs for gear for alts and guild member mains who still need gear.
We have no attendance requirements for raids … we put a raid up on the calendar and, if you want to attend, and can, then you just sign up. We accept people to raids on a first come first served basis. Generally raids tend to have between 20-30 people attending … usually around 25/26 so there’s often a bit of leeway.
We do require people to make an effort if they’re raiding with us … be gemmed/enchanted, flasks, food, research tactics, etc, but equally we’re a pretty forgiving bunch and happy to have people new to raiding along with us.
We can’t “boost” … but as long as people try their best, and be honest with themselves, that’s good enough for us.
We don’t aim to be the best on the realm … if we’re lucky we finish in the first couple of pages of wowprogress for our realm; we don’t aim for Mythic raids, although we will occasionally dabble if we’re bored, especially nearer the end of an expansion.
We have plenty of people who have plenty of alts and different specs, so we have huge flexibility and lots of help for different classes.
We are also a social guild … we have plenty of members who never raid, or only raid occasionally. We have people who shift work, or who are taking a raiding break, we have people who just enjoy relaxing in WoW with a few pet battles of even gasp fishing.
We also seem to have an ever increasing number of Dutch members in the guild 
Plenty of people run Mythic and Mythic+ dungeons, occasionally we organise other stuff too … for example we had a “Hivemind” evening not that long ago where 10 of us got the Hivemind mount 
If this sounds like it might be for you, check out our realm forum post for more information: