I'm a little late to the party, but I figure it's better for me to share my thoughts on the subject now rather than never.
The first thing I thought of when seeing the change to Shields in 1.1.1. was Kirby's D-air. With it's slow start-up and sad landing lag of course extra Shield Stun would be a big welcome to Kirby's approach/offense options. From what I can tell, however, is that D-air remains unsafe on Shield in general. It may actually be a little more safe, but for practical purposes it's negligible. Depending on how safe it was to throw out against a Shield, this could have been a very useful and powerful attack. Oh well.
Kirby's other attacks also benefited from the extra Shield Stun perhaps a little more than D-air, but again, nothing to the point where Kirby can now attack wantonly. The same can be said of Kirby's ground-based attacks which are now just a little safer on-Shield, such as Tilts or Jabs, but nothing that I have found that can lock an opponent in-Shield or allow for notable pressure and aggro play.
The argument that the 1.1.1 patch is actually detrimental to Kirby has merit. For players who are familiar with fighting against Kirby the Shield Mechanics are generally less detrimental than for the Kirby player. It is, of course, match-up dependent, but Kirby is less likely to force the opponent into a Shield than he is forced to Shield. Also, Shielding is (or, perhaps, was) an oft-used tool to get Kirby in against an opponent who can strike first (usually due to range or speed in relation to Kirby's range/speed options). This, along with globally reduced roll invincibility, can actually hinder Kirby's approach/offensive options.
Kind of silly, huh?
I think the vast majority of players don't keep up with Kirby frame data/tech/meta so a lot of this will be overlooked and overwhelmingly inconsequential. Kirby's just going to do the same stuff he's going to do from 1.1.0 and prior, but other characters will benefit arguably better in 1.1.1/1.1.2 than he does.
Is Kirby viable now?
I think Kirby's always been viable: he's always had the tools to win any given match-up (except possibly vs. Mii Brawler). The problem is that his tools are way harder to use and he doesn't have a easy-win option that a lot of Top Tiers have. The sheer amount of skill and talent required to play and win with Kirby is much greater than many other characters to the point where it's more feasible to play a similar character that does Kirby stuff better. Also, Kirby has plenty of match-ups that may not be atrociously difficult, they certainly can seem atrociously obnoxious to participate in (most notably the characters that play keep-away).
He's going to need a much bigger change to be 'agreeably viable'. It won't be to his speed, because he's intended to be a slow character. It can't be out-right KO power or obviously 'dumb-good' attacks either, because that would just be poor balancing. Something about his risk-to-reward would have to be buffed so that good players who manage to get in are keeping up with their opponents. His combo game with the buffs to D-throw/F-thorw have helped a lot, he just needs something that makes getting a KO more reliable such as: Up Throw knockback, or some sort of way to get a B-air, a Smash Attack, or Stone/Hammer.
That's about all I have to say on the subject.
