There's a bit of weight to what factors you state as to why it looks so shaky out of the teams so far. I wouldn't even go as far as to say the strength of EU is abysmal. If you're trying to compare a region to that of any other region, namely Korea, then you're potentially already shooting yourself in the foot because you produce these "overrated" and "underrated" titles and formulate these unrealistic expectations from time to time. Simply put, if we're just trying to use the particular two teams that faced LCK teams in best of 3 series, I just genuinely believe they didn't do any kind of or as much deep analysis on them given their placement in the standings. But we learned last Worlds to never take competition as that of a pushover. There's focusing on success but first there needs to be an idea as to what you'll be up against. Plain and simple.
I'll just start with the main point in the topic: An 8th place and 10th place LCK team looked better than expected. Any and every other social media facet has already pretty much turned a vast pool of users into these bandwagon bullies as this is such a big deal, just like any other major gap match involving an upset in regards to a Korean, Korean team, or star player. We've seen this before particularly at IEM 2 years ago: ESC Ever vs TSM (the opening game at least), Team WE's entire Katowice run...and they were 11th domestically. But we brush off the latter one because of whatever reason. This time we see "1st EU nearly lost to 10th KR" or "Top 3/4 EU lost to 8th KR." As much as I dislike when people decide to just burn facts with no substance, these may be facts but it feels like a glass half empty justification.
Note this is ROX and Kongdoo. Coming into the tournament they've been pretty much the beaten and battered by the rest of the top of the LCK league with few hiccups of statement performances at points in game or by wins. There aren't many crucial data points to take off of that if you're a top team, especially in the case of G2 and H2K. But regardless, you need to show any team even that of proper respect and preparation; that likely comes from that of the coaches and analysts side to prepare for.
On the EU teams though, G2 has shown time and time again that they are uneasy when facing unfamiliar competition. At this point, it's almost Lyon Gaming esque (definitively dominated their region; lost often horribly where it mattered at IWCI/IWCQ although close at IWCQ last year). The loss to FW was nothing that shouldn't have been off the table but the degree in which they did is the astonishing thing. I'll get to that momentarily. The 2-1 result to Kongdoo was a line of disrespect caused by their own momentum. Things didn't have to happen but they did. G2 played this "take the challenge" standard and almost lost the entire series for it; in fact made it closer than it should have been. They didn't play by this "ain't broke, don't fix" manner but with 10 bans and 2 phases that style is almost to the discretion of the enemy team. Producing confidence first in your own team play in response to what your opponent can play is one component to what makes strong teams actually strong.
The case for H2K is different however. Theirs involved what has plagued their team since the start of the split and was effectively exposed by ROX in particular (and somewhat by HKE for that matter): that thing is their synergy. It goes back to the topic on data points; you're this lower table team and you see H2K at the top half of the standings. You can see where they're strong and where not clearer than you could if they were at the bottom. At the bottom on equal footing it just becomes a match of who plays better on the day. And simply put, upsets happen as a result.
UOL is potentially the most solid team at the tournament so far among the EU teams, playing their composition to its strengths (and safely) vs Kongdoo and holding their own vs Flash Wolves despite the 2-0 loss. Not much to discredit against UOL aside from where they were strong and where they weren't (ie: Xerxe). But this is where I get to that of the FW, where for some reason, I barely see a hint of respect for FW as a team prior to this tournament and all of a sudden it's like "Oh right. This team does exist, has these players, and is still undefeated in their region." If that's a definition of underrating, I don't know what is. Both teams made changes, one sooner than the other which potentially tipped the outcome back then. This was just a matter of the better team winning but the losing team not getting absolutely rolled over.
Of the 3 EU teams, UOL gets a slip past my criticism even if they lose to G2 (might I add they face ROX in semis). It's the other two who have been to that Worlds stage that disappoint me. But this doesn't make me even come close to classifying the region as anything of a wildcard; that'd be a major insult at this point, especially if you don't watch the LPL this season so far. Domestically, this is the only region where there's already a clear idea as to where the teams fall on the tier ladder from top to bottom; LMS and LCK can almost identify that once the middle of the table becomes clearer. But should this be an idea of EU's overall strength? Yes. Should this tournament be regarded for any future expectations? No - hasn't been that way for previous years. TSM vs WE - clean sweep and yet outright brushed under a rug just because of the whole "no Korean team" thing and weight of opponent. SKT vs FNC; same result - brushed under a rug only this time people will bring it up because of Korean team involvement/it was SKT. What happens if ROX makes it to the finals...and loses? We'll brush that under a rug too? Point is I don't see this tournament as much of the same even if no European team comes out on top. The backlash however will be abundant regardless but when is it not if it doesn't involve NA, EU, Uzi, EDG, or KR talent, once again underrating any of TW?