This kind of justification makes me... uncomfortable. I've seen it more places than just here too. It seems that we are leaning towards the outcome of a fight being decided more and more by what happens in the actual ten seconds or so of engagement rather than the positioning and resource expenditure of the previous thirty seconds, or the items bought five minutes ago. Justifications like "counterplay" are used to rationalize more power in kits and less on items, or skillshots rather than targeted damage. Resources have become less important with many manaless champions seeing play, and even mana users tend to forget about the resource after an item or two.
The problem here is that tactics is being emphasized more than strategy. MOBAs as a genre appeal differently than say FPS games in that you have persistent power that can dramatically change over the course of a game. One or more players can "carry" the team to victory, and both the successes and failures revolving around carries make the game more interesting. If that's gone, it's easy to feel powerless to make up for a struggling team. Shut-down gold, for instance, becomes less meaningful when items like armor are less powerful.
When we emphasize tactics, twitch reflex and teamwork become more important than individual performance and anticipation. It's like we've forgotten that it's both frustrating and fun to win or lose by fighting or becoming the player that carries the game. It's like we've forgotten that buying a Banshee's Veil to block that Annie nuke is arguably purer counterplay than sidestepping a Veigar's Baleful Strike. By allowing counterplay in anticipation the game becomes more cerebral. Encounters aren't won or lost by a tenth of a second swing.
As it is, it feels like the game is leaning towards something that might be very tense and entertaining to watch, but is not that much fun to play. League was fun because it wasn't like a twitch shooter. That's less true now. "Skill, not stats," is a worrisome philosophy when stats tend to be determined by things that absolutely should matter, such as anticipatory counterplay (buying items) and past performance (how well you've performed so far in a given game).
And come to think of it, aren't squishy champions supposed to take more damage? If there's a problem where a skill has to either deal too much damage to squishies or too little to tanks, shouldn't we be looking at the balance between squishies and tanks rather than trying to cook questionable damage calculations into skills like this?