I hugely disagree about saying the there's no talent gap.
You can see that there are not SO MUCH difference between the BEST teams from each region. But that was only showed in this tournament because there's only team from each region.
If we had a tournament with 20 teams, 4 from each 'big' region, you would see more clearly how the talent depth compare.
Meanwhile the players in the best team for each region might not have too much of a difference, they are not necessarily the best in their region, and their strength doesn't show how deep the region's talent is.
Example:
EDG. Only Koro and Deft is clearly the best in their roles in LPL. by 'clearly' i mean that it's undeniable, not that it's a huge difference to the 2nd place. (keep in mind that Deft is not playing his best form in MSI). While you think NA-EU top 2 players are not far from EDG players, there are many of these in LPL as well, there are many chinese/korean players in LPL that are as good or even better than EDG's guys.
The talent pool has surely a big gap. IT doesn't meant that somewhere in the future NA-EU can't become world champion, but also you can't just deny that.
While i disagree with my friend /u/wildhawk when he said LSPL is better than LCS (i disagree because top LCS teams are more experienced and still a better as teams, besides QG), the talent there will just make it grows. Even if all Koreans suddenly go back to Korea, there will still be famous/great players to form 8-10 competitive teams.
Meanwhile the adc talent Fell pretty hard, the Top-Junglers in China are popping like Crazy, and there are still many crazy talented guys that are unknown to western fans but we can rate them as deserving to be in the 'talent pool'.
One of my favorite things to do during boring classes is to create power rankings by role. Knowing every LSPL and LPL player, i make a top15 for each role and start comparing and imagining stuff. If we took top5 for each role and compare to other regions, it would be a bit silly, and the gap would be even higher between 6th-10th best LPL players and 6th-10th best LCS players. This is what we call 'depth'.
TLDR; The skill level between EDG-Fnatic-AHQ-TSM-SKT might not be as big as before (even tho i think EDG's players are yes more skilled than ahq-tsm-fnc), but comparing the whole scene there are still big differences.