Frankly, I was a tad disappointed. Frankly, I was a tad disappointed.

Personally I would say "a tad bit", but this is also fine.

Frankly, I was a tadbit disappointed. Frankly, I was a bit disappointed.

Alternative phrasing, sounds a bit more natural to me.

Despite the average proficiency level there being complacently high, the way the whole event had been organized was rather underwhelming. Despite the average proficiency level there being complacently high, the way the whole event had been organized was rather underwhelming.

I've always used the word "complacent" to mean unconcerned, uncritical, or oblivious. For instance, "to be complacent about systemic injustice". However, some dictionaries list definitions which imply smugness, and although a complacent person can be smug, I've never used this word like that. I guess some people use this word differently though? Whatever the case, it sounds odd to me. Complacency implies laziness and a lack of knowledge, so having a "complacently high proficiency level" feels paradoxical to me. Although, maybe "complacently knowledgeable" could be an interesting way of saying one has knowledge without wisdom. I don't know. If you want to imply that these people were really smug, I might say something like "pompously".

Despite the average proficiency level there being complacentlyrather high, the way the whole event had beenwas organized was rather underwhelming. Despite the average proficiency level there being rather high, the way the whole event was organized was rather underwhelming.

Was sounds slightly better here since the organization was, presumably, still relevant/on-going

Despite the average proficiency level there being complacentaratively high, the way the whole event had been organized was rather underwhelming. Despite the average proficiency level there being comparatively high, the way the whole event had been organized was rather underwhelming.

I think comparatively is the word you're looking for.

The main problem was that there were so many participants and so little opportunity to speak out. The main problem was that there were so many participants and so little opportunity to speak.

The main problem was that there were so many participants and so littlefew opportunityies to speak out. The main problem was that there were so many participants and so few opportunities to speak.

I think "little" would slide when speaking but it does feel a little off. "Little" sounds right with "opportunity" though. ie. "Even having been given so little opportunity, he prevailed." Gee, I can't really explain what's going on here...

The main problem was that there were so many participants and so littlefew opportunityies to speak out. The main problem was that there were so many participants and so few opportunities to speak.

Speak out (about something) is normally used for protesting in my dialect.

Everyone wanted to add their two cents, creating more likeof a queue to hold a monologue than a space for constructive book discussion. Everyone wanted to add their two cents, creating more of a queue to hold a monologue than a space for constructive book discussion.

Everyone wanted to add their two cents, creating more like a queue to hold a monologue than a space for constructive book discussion. Everyone wanted to add their two cents, creating more like a queue to hold a monologue than a space for constructive book discussion.

Just a note that queue is British English, in American English we use line.

Everyone wanted to add their own two cents, which creatinged more like a queue to hold a monologue than a space for constructive book discussion. Everyone wanted to add their own two cents, which created more like a queue to hold a monologue than a space for constructive book discussion.