I am okay with Irene having more votes than Natsu in the group matches. Keep in mind that we allow for 4 votes per person, so there's a really solid chance that everyone who voted for Natsu also voted for Irene. We know for a fact that some people simply refuse to vote for Natsu out of bias, so I imagine that would be where the difference comes in. Then there's some people who genuinely believe Natsu would get eliminated by the competition, and that should account for 2-3 votes.
Also, my own personal opinion is that Irene stands a fair chance against Natsu. Sure Natsu might be able to beat her if he lands demolition fist in dragon force, but Irene also stands a good chance of breaking all his bones with a claw swipe.
Sure, Irene could probably come close to killing August if she crushed him underneath her claws, but the chance of that happening against a healthy and full-powered Natsu/August is extremely small.
A top tier like Natsu and August would not be waiting for Irene's claw to swipe them off their feet (like Erza). Irene's claw swipe didn't strike me as exceptionally fast, and it's not like Natsu starts off exhausted, similar to Erza against Irene.
Saying Irene gets
80 votes because of one claw swipe is really a stretch...
In terms of dragonification, Irene's transformation is quite slow.
In the manga, it took her several panels/pages before she turned into a full-fledged dragon. Any Dragon Slayer here would be fully ready by the time Irene transforms.
And keep in mind, you only need a dragon slayer like Wendy to pull off reverting Irene.
Mashima introduced Dragon Slayers into the manga for a purpose. And I think Group A was a good opportunity to showcase that.
Also, Natsu's DF Demolition Fist would be more than enough to oneshot Irene, regardless of whether she's in her dragon/human form.
Irene's human form is already
sub-par to Erza + Base Wendy.
Irene's dragon form could be
instantly reverted by DF Natsu, or any other dragon slayer for that matter.
There's no contest here as far as I'm concerned. Irene doesn't have the durability in neither her dragon nor human form to stand a chance against any of the other dragon slayers in this match.